Our rankings are based on registrations of 2006 and 2007 model-year vehicles in the first five months of 2006, for the entire U.S. We chose to base our rankings on percentages of male versus female registrants, as opposed to raw totals of male-registered and female-registered cars, because a car with 100% male registrants is clearly a guys' car, regardless of its sales volume (we required no minimum number of registrations for the cars on the list). A car with over 100,000 male registrants could sound like a guys' car--but it could be a high-volume vehicle with 100,000 female registrants too.
Of course, registration data does not necessarily tell us who is driving the cars -- parents put their kids' cars in their names; husbands put their wives' cars in their names and vice-versa--but it is the closest we can come to understanding gender demographics in new-car purchasing.
