Ok - don't know if iit' recursive, but it's the word i'm using

As an exercise, i'm tracking the team and player stats for my favorite NBA team. What i want is a field defintion that tracks certain stats "fro the season" after each game. So i don't want it to dynamically change after every ggame.

I want to know the teams FG% after game six (which includes games 1-6) and then after game seven (which includes games 1-7), and i want to be able to look at them in comparison, maybe for graphing later on.

Anyone have any idea how to do what i'm talking about?