Home button no longer responding to slight touches

I have had my iphone 4S for awhile and me and my girlfreind have been noticing that my home button is slowly becoming less and less responsive. The home button is requiring more and more force in order to register as a push.

It is currently functioning however the force required is not something i feel comfortable subjecting my phone to on an ongoing basis and double pressing in order to achieve multitasking is horribly inaccurate. it will frequently only register one push of the button