Is this normal Galaxy S3 battery life?

[A]

Finished charging at 100% last night at 1ish AM.
Sat idle until I woke up at 8:30 AM (and then, when I woke up, battery was about 85%).
I've been at work for most of the day, so I didn't even use my phone much besides about 15 minutes of video watching on YouTube; maybe 30 minutes of Facebook/Tumblr/Twitter usage combined; about 15 min of texting.
It's 6:30 PM now, and my phone has 33% battery life left. The screen on time is only at 1 hr 5 min now.
Is this average battery life? Or is there something defective with my battery that I should have checked out? I just think I should have more battery life left if I haven't been using it much today.