Join the businesses who have begun to edge out competitors by scouring the web for alternative data.

It's no wonder that America's best-selling used cars would somewhat reflect its best-selling new cars because, after all, new cars ultimately become used.

But that's not always true, because a) people hold onto some cars longer and b) people go after particular used cars for their perceived aftermarket value.

So it's interesting to see which cars are selling best at CarMax, America's largest used-car dealer.

Topping the list is the Nissan Altima, with 38,940 cars sold since September 2015 (the extent of our data trail). It leads the pack by quite a bit, which is especially interesting as the Altima is not America's best-selling new car, according to USA Today. That honor goes to the Honda Civic, which, according to our CarMax data, sits at 5th place with 25,536 units sold.

This could be because people are snatching up all the Altimas they can because of perceived after-market value. Either way, it's a great seller on the used market.

What are the most popular model years of the Altima? Yes, we have that data:

2014: 12,039 Altimas sold

2015: 10,254 Altimas sold

2013: 9,172 Altimas sold

In this case, we see the 2014 Ford Escape is the overall best-selling model year/vehicle with 13,672 units Coming in a close second with 12,039 is the 2014 Nissan Altima once again.

(Thinknum estimates sold-car data indirectly, by filtering cars that drop off of of Carmax's public listings. Since Carmax allows 30 days for returns, we then track them for an additional month to make sure they don't get returned to the market.)