Americans are Expected to Bet Over $10 Billion on March Madness The numbers come from estimates released by the American Gambling Association (AGA). According to ESPN, who reported the numbers, only three percent of all betting is expected to take place legally. The AGA reports that last year, 24 million people participated in NCAA Tournament pools, submitting over 60 million brackets. Many Americans take part in paid-entry pools which, according to the AGA, are actually illegal in most states. Our current sports betting laws are so out of touch with reality that we're turning tens of millions of Americans into criminals for the simple act of enjoying college basketball. The NCAA Tournament kicks off on Tuesday, March 13 at 6:40 p.m. on TruTV.