Ever wondered which vehicles make manufacturers the most money? So did auto industry analyst Max Warburton. Together with his London-based team at BernsteinResearch, he came up with a list of the most profitable vehicles manufactured since 1990. Automotive News reported Warburton's findings today, with Ford's venerable F-Series truck topping the list.

According to Warburton, the key elements of a "cash cow" vehicle are high price, large production volume, and long production runs, which help spread the cost of development over a long period of time. When looking at the top 12 most profitable cars, three distinct categories emerge: Japanese mid-size sedans, German luxury cars, and American full-sized pickups.

Warburton says Japanese sedans had the most difficult time landing on this list, as their relatively low price points made profits per unit less substantial. Still, the other two factors -- large sales volume and long production runs -- allowed models like the Toyota Camry and Honda Accord to make the list. German models like the venerable BMW 3 Series, 5 Series, and Mercedes-Benz E-Class fill out the list, with their combination of high price and production numbers.

The big money-makers, however, came from the good old U.S. of A. Thanks in large part to their massive sales volumes, the Ford F-Series topped the list, followed by GM's Chevrolet Silverado and GMC Sierra, and the Dodge Ram. Combined, these three American trucks generated $108 billion in before-tax profits since 1990, just about equal to the profits of the rest of the list put together.

THE BIG-BUCK DOZEN

Bernstein Research's 12 most profitable vehicles since 1990.

1. Ford F series

2. GM full-sized pickups

3. Dodge Ram

4. Mercedes S class

5. BMW 5 series

6. BMW 3 series

7. Mercedes E class

8. Lexus RX SUV

9. Jeep Grand Cherokee

10. Honda Accord

11. Porsche 911

12. Toyota Camry