Collected 3 rejection notices for the manuscript so far. All very gracious, "Sorry it's not suitable for us but thanks for trying, best of luck etc." I've sent 11 query letters to agents... the other 8 haven't responded.
A friend and brilliant writer, Dan Moran, once told me you can't say you've really tried unless you sent out a hundred queries. You can check out more info about Dan and his Continuing Time science fiction novels over at his site.