Wagering on U.S. horse races continued to plunge in March of this year when compared with the same month last year, dropping nearly 10 percent, or $100 million, even as purses rose significantly because of takeout increases in California and new casino subsidies in Florida. Wagering in March was $899.3 million, down from $998.7 million in March of last year, according to figures released on Monday by Equibase, continuing a long stream of month-to-month declines affecting horse racing. The decline was exacerbated in part by a 4.2 percent reduction in race days during the month. Despite the declines, purses distributed through U.S. races during the month rose 6.1 percent, from $73.8 million to $78.3 million, according to the Equibase figures. The boost was almost entirely tied to a 25-percent increase in purses distributed at California tracks because of a takeout increase that went into effect on Jan. 1, and a new law in Florida that has allowed tracks to retain a greater share of revenue from slot machines. Purses at U.S. racetracks are heavily subsidized by slot machines, insulating the industry somewhat from the precipitous declines in wagering handle. According to the figures, through the first three months of 2011 handle has declined 8.5 percent, from $2.79 billion to $2.55 billion, while purses have increased 5.3 percent, from $194.3 million to $204.7 million. Race days have declined 1.8 percent, from 1,048 to 1,029. DRF MORNING LINE: Get out of the gate fast every day - sign up for DRF's free newsletter