American motorists bought a record 17.5 million new vehicles in 2015. While automobile sales are at an all time high, certain makes and models are in much higher demand than others.

The total units a manufacturer sells of a specific vehicle model is a reflection the vehicle’s popularity. However, demand for a given vehicle can also be measured by the average number of days it sits on a dealer’s lot before it is sold. In order to determine America’s fastest-selling cars, 24/7 Wall St. reviewed Kelley Blue Book days to turn figures — or, the number of days a car sits on a dealer’s lot before it is sold. Average days to turn in 2015 ranged from 231.7 for the Honda Insight to 16.0 for the Subaru Outback.

While none of the fastest selling cars rank among the best selling cars of the year, they all have had meaningful year-over-year sales increases. Sales of the Volvo XC90, a vehicle that spends an average of just 22.7 days on the lot before being sold, shot up 223% from 3,952 units in 2014 to 12,777 units in 2015.

Click here to see the cars so hot they’re out of stock.

Click here to see the cars American’s don’t want to buy.

Many factors can contribute to demand of a particular vehicle. Perhaps the most universal and unchanging factor is the manufacturer’s reputation for quality. In an interview with 24/7 Wall St., Tim Fleming, analyst at Kelley Blue Book, explained that quality is the most important factor. “If you have good products out there, it gives the dealers a better chance to sell,” Fleming said. The majority of the fastest selling cars are manufactured by one of the top 10 car makers in overall quality as ranked by Consumer Reports. Audi and Subaru, the two car makers with the highest quality ratings, manufacture four of the fastest selling cars in the United States.

Another characteristic many of America’s fastest-selling cars share is their relatively recent introduction to the market. “Demand is highest when [a] model just launches,” Fleming said. Perhaps not surprisingly, more than half of the cars with the lowest days to turn were not available as recently as 2013, and one-third of them were new for 2015.

Consumer tastes and sales trends in the auto industry have recently been influenced by lower fuel prices. Gasoline prices across the country hit an eight-year low in 2016, part of a long-term downward trend that began in 2014. Lower prices at the pump have lead to a surge in popularity of SUVs and crossovers.

Car sales have decreased 5.9% year-to-date compared to the same period in 2015, while SUV and crossover sales have shot up by 8.8% over the same time period. “Consumers gravitate towards SUVs or trucks, and as a result, the cars take the brunt of that and become less popular,” said Fleming. More than half of the fastest selling vehicles in the U.S. market are SUVs.

To determine America’s fastest-selling cars, 24/7 Wall St. reviewed days to turn figures provided by Kelley Blue Book, vehicle research and valuation site. This figure measures the average number of days a particular model spent on dealers’ lots following its arrival until it was sold in 2015. Additionally, Kelley Blue Book provided figures on U.S. sales by model for 2013, 2014, and 2015. We also reviewed monthly sales releases published by auto manufacturers. Manufacturer’s suggested retail price (MSRP) figures, come from the manufacturers’ websites.

These are the cars so hot they’re out of stock.

15. Q3
> Make: Audi
> Avg. days to turn: 24.8
> 2014-2015 sales change: +262.0%
> Starting MSRP: $33,700

New car brands are more likely to spend very little time on dealership lots as they are often more enticing to auto buyers. This, as well as currently high demand for SUVs and crossovers likely contributed to Audi Q3’s extremely low days to turn. The luxury brand’s crossover model was introduced in North America in 2014 and spent less than 25 days on average on the lot in 2015 before being sold.

14. iA
> Make: Scion
> Avg. days to turn: 24.5
> 2014-2015 sales change: N/A
> Starting MSRP: $17,595

Most of the cars that spent relatively little time on the lot last year are part of a brand that is in high demand. Toyota’s Scion division, on the other hand, has been underperforming for years. The manufacturer announced in February it will kill the brand, including the iA, which was just introduced in 2015. It is no surprise that the average iA spent relatively little time on the lot before being sold, as the model was not even available for the entirety of the year.

13. Legacy
> Make: Subaru
> Avg. days to turn: 24.0
> 2014-2015 sales change: +15.6%
> Starting MSRP: $21,745

Brand new models and redesigns tend to be appealing to car buyers. While the Legacy brand has been around for more than two decades, Subaru introduced a fully redesigned generation of the mid-sized sedan in 2015. Sales of the Legacy jumped 15.6% compared to 2014, and the average model spent just 24 days on the lot before being sold.

12. TT
> Make: Audi
> Avg. days to turn: 23.1
> 2014-2015 sales change: +0.8%
> Starting MSRP: $42,900

While 2015 sales of the Audi TT were up slightly from the previous year, they were down considerably from 2013. Audi sold 2,053 TTs in 2013, nearly double the number of units sold in 2015. Despite the two-year sales decline, the TT does not sit long on dealership lots. Earlier this month, the German auto manufacturer introduced a far more powerful version of the TT for the 2017 model year.

11. XC90
> Make: Volvo
> Avg. days to turn: 22.7
> 2014-2015 sales change: +223.3%
> MSRP: $45,950

The newest generation of Volvo’s popular crossover arrived at dealerships in the spring of 2015. After its introduction, the Swedish car maker reported a dramatic spike in sales of the XC90. In 2015, Volvo sold, 12,777 XC90s, more than triple the units sold the previous year. Tremendously popular, the XC90 only sat on the lot for an average of 23 days before being sold.

10. Range Rover Sport
> Make: Land Rover
> Avg. days to turn: 22.4
> 2014-2015 sales change: +19.9%
> MSRP: $64,950

In 2016, gas prices across the country hit their lowest point in eight years. With falling prices, SUVs have gained popularity. The Range Rover Sport, an SUV that gets a relatively low combined 19 mpg, is one of the fastest-selling cars in the country, remaining on the lot for an average 22 days in 2015 before being sold. While many of the fastest selling cars are relatively new, the Range Rover Sport was released a decade ago and is still in its first generation.

9. Macan
> Make: Porsche
> Avg. days to turn: 21.6
> 2014-2015 sales change: +86.9%
> MSRP: $47,500

Macan made its debut in 2014. That year, Porsche sold 7,241 units. The following year, sales of the crossover SUV nearly doubled and the Macan became Porsche’s fastest-selling vehicle. Macans sat on dealers lots for an average of only 22 days before being sold in 2015. The Macan is a slightly less expensive cousin of the Cayenne, the only other crossover SUV sold by the German automaker.

8. GLE
> Make: Mercedes-Benz
> Avg. days to turn: 21.5
> 2014-2015 sales change: N/A
> Starting MSRP: $51,100

One-third of the fastest selling vehicles were introduced in 2015, and the GLE is one of them. Across the country, Mercedes-Benz dealerships kept the luxury SUV on the lot for an average of only 22 days, more time than only a handful of other makes and models. Demand for the GLE coincides with the re-surging popularity of SUVs, due in large part to lower gas prices. The GLE only gets 18 mpg in the city and 24 on the highway.

7. 4Runner
> Make: Toyota
> Avg. days to turn: 20.8
> 2014-2015 sales change: +26.2%
> Starting MSRP: $33,810

Gas prices hit an eight year low in 2016 following a long-term downward trend beginning in 2014. One consequence of lower fuel prices has been a resurgence in popularity of vehicles with relatively low mpg ratings. SUVs comprise more than a third of the fastest selling vehicles, and the Toyota 4Runner is one of them. Toyota sold 97,034 4Runners in 2015, up more than 26% from the year before.

6. Metris
> Make: Mercedes-Benz
> Avg. days to turn: 20.2
> 2014-2015 sales change: N/A
> Starting MSRP: $28,950/ $32,500

Mercedes-Benz is known primarily as a luxury brand, but not all of its vehicles are exceedingly expensive. The brand-new Metris, the van the company introduced in 2015, costs relatively little compared to most Mercedes with an MSRP of $28,950 for the cargo version and $32,500 for the passenger van. The Metris only went on sale in October, which partly explains why the models sold in 2015 spent such a low average time on the lot.

5. i8
> Make: BMW
> Avg. days to turn: 19.3
> 2014-2015 sales change: +308.1%
> Starting MSRP: $140,700

The BMW i8 is a hybrid sports car with both an electric motor and a fuel engine. Introduced in 2014, BMW sold 555 units of the i8 in the first year. Sales spiked 300% in 2015, when the German automaker sold 2,265 units. On average, i8s spent less than 20 days on the lot before they were sold in 2015. According to Fleming, the i8 is so popular because there is nothing else like it on the market.

4. GT
> Make: Mercedes-Benz
> Avg. days to turn: 18.7
> 2014-2015 sales change: N/A
> Starting MSRP: $129,900

Brand new models tend to capture the public’s attention and are far more likely to spend relatively little time on the lot before being sold. The GT class, which first became available in April 2015, is a high-end luxury model with a base MSRP of $129,900. That the car was not available the entire year and that so few are sold — less than 1,300 through the entirety of 2015 — likely contributed to the model’s low days to turn.

3. Highlander
> Make: Toyota
> Avg. days to turn: 18.2
> 2014-2015 sales change: +8.8%
> Starting MSRP: $29,990

The Toyota Highlander was one of only five vehicles to sit on the lot for an average of less than 20 days in 2015. More Highlanders were sold in each of the last three years than any other vehicle on this list. Sales of the the Japanese automaker’s crossover SUV were certainly spurred by the brand’s overall popularity. Toyota sells more cars in the United States than any other foreign automaker.

2. HR-V
> Make: Honda
> Avg. days to turn: 17.7
> 2014-2015 sales change: N/A
> Starting MSRP: $19,215

The HR-V, honda’s new subcompact crossover SUV, debuted in May 2015. Between the high appeal of newer models, the current demand for SUVs and crossovers, and the fact that the car was not even available for sale the entire year, it is no surprise that only one model spent less time on the lot than the HR-V before being sold last year.

1. Outback
> Make: Subaru
> Avg. days to turn: 16.0
> 2014-2015 sales change: +9.7%
> Starting MSRP: $24,995

Subaru is one of the hottest car brands in the country, breaking its annual U.S. sales record in 2015 for the eighth consecutive year. Sales of the brand’s Outback model, which is second only to the Forrester as the most popular Subaru, increased by 22.7% through the first three months of 2016 compared to the same period in 2015.

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