AVG(Count) nested aggregation

[Joosh]

I'm trying to get a YTD average of a count of employees

I use this formula to count the employees

COUNT(Global Career Band) in a line chart, my date field is called MonthName, in format 'MMM-YY'

How can i use this chart to show a YTD average, so on January it would show 27257, but on february it would take the average of february and january and so on.

Thanks

[Joosh]

I've updated it to use the {1} in the set analysis to ignore all selections. and it still is not liking it.

Josh