How much formula should my daughter be taking?

My daughter is 6 1/2 months and is eating pureed fruits and veggies 3 times a day now. I was just wondering how many ounces of formula she should be taking each day now that she is on solid foods? I know that when they're on just formula they need to be drinking 24-32 oz a day. Is it still the same for when they're on solids, or can they take less? My daughter is drinking approximately 21 oz each day. Should she be taking more?