Because football was more popular in Mexico before it was in the US and they brought it over to the US.
America and Chivas.
there is the women's us soccer team.
Sporting Kansas City, LA Galaxy and New England Revolution are some top soccer teams in the US.
There are currently 15 official national teams.
There are currently 19 teams in MLS.
There are 13 teams playing in the MLS (Major League Soccer) and 9 teams playing in the MISL (Major Indoor Soccer League).
The best thing to promote US soccer will be to improve Major League Soccer level. - More teams competiting in MLS (like 16 or 20) - End of the "Franchise" system, or creation of a lower division to create a European "two sided" competition : those who want to win, those who don't want to die. - More "stars" allowed in US teams - More international/continental confrontations with other teams (especially Mexican, Brazilian, Argentinian) I think it really promote US soccer :)
I believe its the bald eagles
By pro I guess you mean MLS which is the first tier of American soccer, in that case it's 15 teams.