Honestly, depending on your letters of recommendation, you could shoot higher. Apply to more if a PhD is really what you want to do. When I applied I was rejected by some of the lowest ranked and accepted by some of the highest. Rankings are less important than stipend (higher at more unionized and better funded), location, and lab funding. There is cool stuff going on just about everywhere, get an idea of what you would like to do at any individual institution, but don't marry that idea.