My 32 warlock has 15 hours, with heirlooms and queuing with a friend as tank. So your rate seems about the same as mine.
I should check my playtime on my mains
Warrior (old main)
Total: 65 days, 21 hours
This level: 56 days, 1 hour
Hunter (new main)
Total: 25 days, 2 hours
This level: 19 days, 1 hour