Years ago, I had a discussion in comments with Noel Maurer about the relative popularity of different sports. He thought baseball was more popular than I did, and the whole thing got rather heated; we were on the verge of a knife fight until Jim Brown stepped in with one of his famous mediations, and we agreed to wait for a poll to settle the argument.* Well, here is just such a poll from Mitofsky. Turns out, as a proportion of the total population that likes watching and/or follows a given sport, the order goes: soccer, boxing, baseball, basketball, American football, and golf. I'd say that order makes me wrong in the initial dispute.
Given the poor showing of American football, it's interesting how much NFL action you find on the TV; if I remember correctly, you get at least five games a week with basic cable. I imagine that reflects a combination of wealthier fans and disproportionate popularity of football in the Mexico City area.
*Not actually true.