Total wagering on U.S. Thoroughbred races in May declined slightly compared to the same month last year, according to figures released by Equibase on Monday, but a larger decline in the number of races in the month boosted the average wagering per race by 5.7 percent. Although total wagering fell 1.54 percent to $1.39 billion, the average wagering per race in May jumped from $435,350 last year to $460,404. The number of races held in May this year dropped 6.9 percent, from 3,249 in May of last year to 3,025 this year. May of this year included eight weekend dates, compared to nine weekend dates last year. During the month, two races of the Triple Crown were held, the Kentucky Derby and the Preakness stakes. Wagering on the Derby, boosted by a surge in straight wagering on the race due to the Derby’s availability on a large sports-betting platform for the first time, was a record, while betting on the Preakness fell, largely because of a shorter field when compared to the race last year. :: Take your handicapping to the next level and play with FREE DRF Past Performances - Formulator or Classic.  Due to the decline in races held, total purses distributed during the month fell 2.7 percent, from $120.31 million to $117.01 million. The average purse per race, however, was up 4.5 percent, from $37,029 to $38,706. Purses at racetracks in the U.S. are heavily subsidized by casino revenues. The average field size for a race in May jumped 4.3 percent, from 6.86 horses per race to 7.16 horses per race. Year-to-date, total wagering is down 2.8 percent, while the number of races held is down 1.29 percent. Total purses distributed through May is up 2.85 percent. Average field size is up slightly, by 1.89 percent, from 7.33 through May of last year to 7.47 this year. :: Want to learn more about handicapping and wagering? Check out DRF's Handicapping 101 and Wagering 101 pages.