Any of these functions will allow you to count uniques:
=SUMPRODUCT((A2:A78<>"")/(COUNTIF(A2:A78,A2:A78&"")))
=SUMPRODUCT((A2:A78<>"")/(COUNTIF(A2:A78,A2:A78)+(A2:A78="")))
=SUM(IF(FREQUENCY(IF(LEN(A2:A971)>0,MATCH(A2:A971,A2:A971,0),""),IF(LEN(A2:A971)>0,MATCH(A2:A971,A2:A971,0),""))>0,1))
(this last one is a CES function; ctrl + shift + enter...not just enter)
I'm not sure what you mean by 'populate new cells'. Can you elaborate?
Regards,
Ryan---