Formulas: Averages

I would like to know how to create a "To-Date" average. For example, lets say
I have 3 dates:

Nov 1
Nov 2
Nov 3

and I have numerical values for each date:

Nov 1 | 100
Nov 2 | 106
Nov 3 | 88

How could I get an "to-date" average where it will average every number up
to that number together. For example, the aveage that would display to the
right of Nov 1 is 100 [100/1], to the right of Nov 2 is 103 [(100+106)/2],
and to the right of Nov 3 is 98 [(100+106+88)/3]. I know the parent function
for average is =Average().

I just need a formula that recognizes the current number and the ones before
it.