If you're only interested in the year part, you could use:
=IF(LEN(A3)<5,A3,YEAR(A3))

In a situation where some data have only years and other data have months & years, that would seem to be the most consistent way of analysing them; otherwise you'd need to analyse the data with months & years separately from the data with years only, to avoid skewing the analysis.

__________________
Cheers,
Paul Edstein
[Fmr MS MVP - Word]