=SUMPRODUCT(--(A1:A20&""<"")/COUNTIF(A1:A20,A1:A20&""))

--
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HTH

Bob

(there's no email, no snail mail, but somewhere should be gmail in my addy)



"orquidea" wrote in message
...
HI

I have a list of series like this

serie 165125
serie 165126
serie 165127
serie 165125
serie 165126
serie 165124
serie 165125

I want to count how many series I have. The formula have to consider that
some series are repeiting in many rows. ei in the list above will be 4
series.

Could anyone help me please.

Thanks,
Orquidea