Remember zapping ants with a magnifying glass?

I always wonder about how the electricity used to charge hybrids is factored in to the "MPG" claims. When folks say "I get > 50mpg", is that after they've bought whatever electricity the car needs for recharge?

MPG is really an economic factor, and it seems to me that "fuel use" ought to somehow account for whatever electricity is being consumed by the car.

Are there "energy use per mile" figures, expressed as a total of energy units(?) combining both gas and electric?