Counting Data between Decades

[countryfan_n]

Hello friends,

The attachment here includes the CDs listed in my itunes.

I need a formula that would go thru. column J, and pick the number of CDs that fall between decades 1970-1980, 1980-1990, 1990-2000,etc.

* One condition though, counting should be unique, and ignore repeated rows with same year and the same CD name.

Your help is truly appreciated in advance!
Nawaf

[Bob Phillips]

Try this array formula

=SUM(N(FREQUENCY(IF(($J$4:$J$10>=C13)*($J$4:$J$10<=D13),MATCH($D$4:$D$10&$E $4:$E$10&"",$D$4:$D$10&$E$4:$E$10&"",0)),MATCH($D$4:$D$10&$E$4:$E$10&"",$D$ 4:$D$10&$E$4:$E$10&"",0))>0))