Hardly ever. Since DS was born (12 weeks) I've had 2 glasses of wine when we've been out for dinner, but it's a pain as I have to organise a bottle of EBM for DS while we are out because I won't breast feed him when I've had a drink.
Before I was pregnant, I occasionally (maybe once or twice a month) had a glass of wine with dinner.
To answer your question, 3-4 drinks every day is not normal IMO. If it was once a week maybe, but getting through a carton a week is excessive to me.