1900 is pretty strong. Football always has a much much larger student attendance. Tough to say why, but that's the way it is.
Football in general draws much better than hoops. I'd guess if you compared those numbers to overall total attendance, they'd be similar in proportion. Popularity of football as a sport, ease of following just a single game a week, fewer opportunities to go, etc. probably all play into it.
Honestly, while we should always be aiming to draw more, I'm not disappointed by either of those numbers. Some people don't like sports and will never/rarely go to such events. Some people will invariably be busy or out of town who want to go, and some will have other plans.
There were ~22,600 total students at the Athens campus and of those, ~17,375 were undergrad (grad students/PHD candidates are probably less likely to attend, though some surely do). So at an average football game, roughly a quarter of the student population attended, or about a third of the undergrad population. For hoops, it is in the 8-10% range.
As mentioned, hoops suffers from break games when using an average -- I'd like to see an average for when classes are in session. Still, those seem to me like pretty solid portions of the student body to be in one place in one time as
averages and not peak/typical numbers (when you consider midweek football and winter break basketball).