Home button issues with iPhone 4

I purchased my iPhone 4 back in 2010 when it was first released, and for the most part it's worked well. But lately, as early as a few months ago, Ive been experiencing some issues with the home button. The issue I'm having is that it seems the home button has become unresponsive. What I mean by this is that when I press the home button nothing happens, I am stuck having to push it a second, third, and sometimes a fourth time before it's registered. This happens from sleep, from app to app, from app to home screen, etc. It's generally consistent with no particular software issue or place within the software.

I'm not sure what to do about it. Again it's not that old and I want to make sure I take advantage of the ability to get it fixed or replaced before the warranty is up. Any suggestions would be great. Thanks.