March Madness: Only 0.17% of ESPN Brackets Still Perfect

b_250_0_16777215_00_images_obgrabber_2014-03_fb3fb2fa39.jpgHemera/Thinkstock (NEW YORK) -- It turns out that when Warren Buffett offered $1 billion to anyone who filled out a perfect NCAA bracket for the basketball tournament that started Thursday he was making a pretty safe bet. In ESPN's tournament challenge, more than 11 million people filled out brackets. And now, fewer than 19,000 -- or just 0.17 percent of those brackets -- are still perfect.

While upset winners University of Dayton and Harvard were considered trendy picks in Thursday's games, their victories -- combined with North Dakota State University's triumph over Oklahoma University -- made for quite the bracket-busting afternoon.

“Everything being equal, the chances of filling out a perfect bracket are just over nine quintillion to one,” said Wynn Las Vegas oddsmaker Johnny Avello, “which is a nine followed by 18 zeroes."

And we're just halfway through the second round of the tournament.

Copyright 2014 ABC News Radio