Hopefully someone can help..

I'm keeping youth work statistics and need to track the participation rates of individuals since their first visit.

My spread-sheet has one row per user, with attendances marked as "P" in cells from column M onwards.
Effectively I need to be able to work out when the first attendance was and count all subsequent attendances, then dividing them by the number of cells from the first "P" up to the latest used column (this column might not be used in that particular row - if that person has not attended).

This is a live sheet. so needs to automatically update the ranges as extra attendance columns are added.


The idea is that we will be able to see, at any time, what percentage of weeks a member has attended since their first visit, so that we can target those who look likely to drop out - and potentially need help.

Thanks,

Mike