On average how many diapers did y'all go through?

Amanda
I'm expecting twin di/di girls late May early June. We have started to stock up on diapers already. With our son I can't even remember how many diapers we blew through. 
But on average how many diapers did my fellow twins mommas go through a month? From size premie - size four? I've heard some moms say roughly 700?