He's probably comparing daily usage.
You also have to account for air condition...so look at the average temperature and if it has been much hotter, then it could be another reason since you might be using the AC more. I know I have used my AC more this summer than last (but it is because my dog is getting older and can't take the heat anymore)
OK, Benny, I am going to give you the save your electric rant again...
Look around for anything else that is wasting electric..do you or your kids leave lights on when no one is in the room? How about the TV?
There are plenty of resources to tell you how to save energy. If you save in other ways, you won't mind spending that to heat your tub this winter..