Should retroactive child support be based on current income, or income for each year the order covers?

I have mixed emotions about this. most people will tell you put the child first do what is best for the child. I say depends on the circumstances. If the father was a dead bead and knew about the child and paternatiy was established squeeze his *** dry. If the mother is one of those that decided not to reveal to the man she was carrying his child and made no attempts to get paternity established I say those years are ones she chose and you go from this moment on