I apologize in advance if this is one of those questions that's so common as to be annoying but I've worked so hard on my book for over a year now that I can't help worrying about this. I was recently reading a book of advice for writing science fiction and fantasy. The author said that he sees probably a thousand manuscripts for every one that gets published. Those odds seem depressingly long, though I realize that there are a number of reasons why it may not be that bad. (There are many publishers, most of the books have been submitted multiple times, a sizable percentage are very poor efforts, etc, etc)
Still... if there are 10 publishers, that's still only 1 in 100. Ok, so let's say a typical book gets submitted several times to the same set of publishers before it finally gets through. That still only improves it to 1 in 30 or so.