The Friday File: In 2012, all-source betting on the 138th Kentucky Derby and the 12 race undercard totaled a record $187 million, with $133.1 million bet on just the Kentucky Derby. Last year, the totals were slightly lower at $184.6 million and $130.5 million respectively. Churchill Downs returned 81.6% of all wagers last year and 82% in 2012. I’m going with California Chrome to place and Danza as a longshot.