Trying to compare last years numbers to this years numbers

[markman235]

Hi everyone,

I have a full set of last years numbers that I am trying to compar to a set of this years numbers on a moving 4 week average. I can get the numbers for the current year using this array formula.

=IFERROR(AVERAGE(INDEX('IWI Week Ending Usage Numbers'!3:3,LARGE(COLUMN('IWI Week Ending Usage Numbers'!3:3)*('IWI Week Ending Usage Numbers'!3:3<>""),4)):'IWI Week Ending Usage Numbers'!XFD3),"-")

This works because nothing is populated past the last week. (I can't run production numbers for the future).

My question is, how can I find the numbers for the same week, last year? I was thinking of using an offset based on the formula above to find the week number (they are listed in row 2) and then index match that to the row numbers for last years data (which starts in row 30).

Any thoughts?

Thank you,

Mark