Excel 2007 : Using YEAR() of a range in AVERAGEIF

Apologies if this has already been asked, I couldn't find anything similar on the forum.

I basically have a table of dates (jan 2012, feb 2012, mar 2012....etc etc to dec 2050) and production for each of those months.

I want to produce a cell (say B1) which the user can type in a year (in A1) and it gives average production for that year.

I was trying to use B1=AVERAGEIF(YEAR(Range of dates),A1,range of productions)

This doesn't work, can anyone offer me any advice?

Thanks,

Alice