Late 2011 13" MacBook Pro Battery Capacity

I've noticed the battery on my late 2011 13" MacBook Pro doesn't seem to hold charge for long, I can take the machine off power and it will die within around 90 mins of light usage from 100% down to less than 10%

I've tried a full discharge and recharge cycle and checked the cycle count in System Details (screenshot below):

Any ideas why the battery is losing capacity so quickly? I'm not running any power hungry apps and it even drains quite quickly when sleeping disconnected from power.