Last twelve months turnover rate

[Dominik]

Dear community

I am trying to figure out how to calculate turnover rate of the last twelve month. I like to go back in the past and see what the turnover rate was back then. I'd like also to have a line chart showing me the turnoverrates from the last twelve months by every month.

What I need is the average Headcount from the last twelve months for every month in the past.  I need the same for the leavers (e.g count all leavers from May twelve months back.). Or if I select another month,always count the leavers 12 months back.

and also it would be nice if I am in the actual month (e.g. june) the turnover rate always starts counting from the prev. month (e.g. from may back 12 months)

Any suggestions?

Thanks a lot for your help.

Dominik

[HirisH_V7]

May Be this,

Sum( {<Date={">=$(=MonthStart(Max(Date), -11))<=$(=Date(Max(Date)))"}>}TurnOverRate)/12

[Dominik]

Thanks a lot for your answer. 

But I want the totals per past months each added together and then divided by 12. There needs to be an aggregation per month and then a sum and then a division  11.

Any idea?

Many thanks.
Dominik