OK, SFB actually has 95 performances this year. I don't think 15 fewer performances than that qualifies as "so little". I was comparing apples and apples in terms of audience size when I chose Houston. Perhaps you could look up the numbers for PNB, Joffrey, Boston Ballet, Miami City Ballet, Pennsylvania Ballet...
ABT has 85 performances on its schedule between now and next October, and even counting in their fall season , I don't see how they would get to the 170 you mention.