according to drf:
On the Beyer scale of numbers, the very best stakes horses in the country earn figures in the 120's. Good allowance horses or low-grade stakes horses run around 100. A typical $25,000 claiming race would be run in the low 90s, a $10,000 claiming race in the low to mid 80s. The average winning figure for bottom-level $2,500 claimers at smaller tracks is 57.
A horse who earns a 90 has run faster than one who runs an 80. In this system of numbers, 2 1/2 points are roughly equal to one length in sprints, and 2 points to one length in routes.
http://www.drf2000.com/help/help_howto.html
http://www.drf2000.com/help/help_speedrate.html