Zumba and HRM

I just got a HRM (Polar H7) and have been logging in the first set of numbers. I go three times a week, all different instructors.

45 min class- 397
55 min class- 453
65 min class- 568

Average heart rate around 145.
I'm 46, 5'5" and 215lbs.

Just curious, how many calories do you burn doing Zumba?