Just go into the urban areas of a country, or rural for that matter, and count the names of famous sports players on the kids' backs.
That is, indeed, true. One can also note what they're wearing on their heads. In Southern California, the baseball caps one usually sees are Cardinal and Gold (University of Southern California Trojans football), blue (Los Angeles Dodgers baseball) or red (Anaheim Angels baseball). I'll be wearing my Cardinal and Gold cap this fall as well as well as my Orange and Black Occidental College cap.
At a recent family reunion in Ohio, my relatives, virtually to a man, were Ohio State Buckeyes fans--and not big fans of the Trojans, off-and-on rivals since 1936. Over the border in Pennsylvania, I saw a lot of Pittsburgh Pirates and Steelers hats and t-shirts.