The answer is Texas. According to USA Today, its population only makes up 8 percent of the country, yet its people drive 10 percent of the nation’s pickups. That number is even higher on (gasp) Wikipedia, which states that Texans drive 14 percent of the country’s pickup trucks.
In addition, because pickups are so popular there, registration fees and other expenses are lower than in most states—that’s a good incentive to get butts in seats in trucks. I wish every state was like that, that would be something.