Hi folks.

I'm currently working on a spreadsheet to give a target update for various partners I work with.
I need to work out a percentage value for a quater, which is dependant on the input of a percentage of retail target figure. So for instance I have:
Jan - 125% of retail target
Feb - 60%
March - 100%

I need to show a quater value, which I have come to the conclusion is:
(1-(((1-B8)+(1-B9)+(1-B10))/3)
Which just so happens to be the average value
Which works out as 95%
But if these percentage figures are derived from a actual/target like:
Jan - 4 target, 5 actual
Feb - 5 target, 3 actual
March - 6 target, 6 actual
Then my "true" percentage actual works out at 15 target, 14 actual which is 93.34%

Is there a better way to work out the quartile percentage?