MacbookPro is running too much ram idle (16GB installed)

Hello, my computer seems to be using an excessive amount of ram while sitting idle (3.35GB currently). I did a complete OS re-install as directed by apple but the problem doesn't seem to be fixed. I haven't used a time machine backup so my computer is currently at a factory default stage. When i had everyhing on it before i would max out my ram (15.55GB +/-) only running safari..

Any help would be appreciated.