Ford 2.7 Ecoboost and 3.5 V6 are used on the F-150, which is not your regular car. It is however one of the most popular truck in north america (1st I believe), outselling cars in most states.
So, you can skew the stats however you want depending on how you want to look at it. Overall cars are actually the lesser-selling segment in the US.
1. http://online.wsj.com/mdc/public/page/2_3022-autosales.html#...