No, I can't believe that the URL box is used more than the search one. Thre must be an error or, more probably, a bias towards tech-savvy people. I've seen common people typing full URLs in the Google box.
You're right about the bias. If you use the filters to view only data from self-identified "Beginner" users, then the address bar usage is significantly lower and the search bar usage is higher (but still not as high as the address bar).
