I just took a meter reading, and we used a whopping 11 cubic feet from August to September.
The electric bill, however, was $199 in August. Of course, it was really hot and humid, so the A/C was humming most of the time. (I need to replace it, but it's a job; we have hot water heat, so the air handler has to go up in the attic. Our son is HVAC qualified, and he'll buy and install it for us. All I'll have to do is pay for the parts, about $2000.