What are the annual sales of mountain bike and the street bike in the States?

Answer 1

finance.yahoo.com (no "www")

You can look up financials for publicly traded, some private companies, and often the industry. That MIGHT give you an idea.

Answer 2

You might try posing that question to Bicycling magazine. They have a research staff that looks at that type of data. I have seen comparisons of mtn bike sales to road bike sales in that magazine in the past.