Bernd - thanks for the info.

I am getting an error when I run the fomula. Any ideas? The error is
"#NAME?".

"Bernd P" wrote:

Hello Walter,

Select a sufficiently long area with 3 columns and array-enter:
=Pfreq(A1:A999,B1:B999,C1:C999)

Pfreq you can find he
http://sulprobil.com/html/pfreq.html

Regards.
Bernd
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