How to count with multiple criterias.

Peacefulpeace 

=INDEX(ROW(5:17),MATCH(1,($B$5:$B$17=2009)*($D$5:$D$17=""),0))

Maybe the row number should be returned if the year is 2009 and days booked is empty. You can try this formula. Enter the formula with ctrl+shift+enter if you don't work with Office365 or 2021.