It's great that you're continuing to offer your child the benefit of mama's milk. Relax and rest assured that you can trust your (and baby's) instincts. If given the opportunity, most kids will eat when they are hungry and drink when they are thirsty. Simply continue to offer healthy solids throughout the day and breastfeed when baby wants to breastfeed. The beauty of breastfeeding is that even if your kiddo is going through a picky eating stage, you'll know he's getting excellent nutrition from your milk.
There are no magic percentages, and every kid is different. (Often, every day is different too.) If you are concerned that your child might not be gaining weight, head to the doctor for a weigh-in. He should stay close to his usual percentile on the growth charts. (Remember that growth percentiles are different for breastfed and formula-fed babies. Make sure your doctor has access to a growth chart for breastfed babies from the World Health Organization.)