Thx for your almost perfect answer Daniel.
I made some final adjustments to make the solution more general and also cope with more Employees.
Extra notes on the solution can be found in the attached qvw.
The TOTAL function should be used to make calculations in an expression independent from the dimensions in the chart.
Set-Analysis should be used to make calculations in an expression independent from the current selections.
The solution without the Set-Analysis is most easy to read and understand. But which of both is best from performance point of view?
QlikcomQ4Sol.qvw 236.8 K