€œIssues Log€� records date an issue is raised and a target date to complete
action (this being the date raised + 20 days). There is one issue per row.
I need to count the number of instances where the target date has been
missed, ie where the date completed is more than 20 days after the date
raised. Then I would like to express this as a percentage of the total
issues raised. Can anyone suggest a suitable formula please?

Date Issue Raised Target Date Action Complete
a a+20 a+10
b b+20 b+21
c c+20 c+30

Count if action completed in more than 20 days