Add a set series of numbers to a column of repeating values

Hi everyone,

Ram has been assisting me with an excel 2010 issue I have, but I had a thought which I figured might be a totally separate solution.

What I have is column A with a series of repeating values that that are of different lengths like the following:

XXX
XXX
XXX
YYY
YYY
YYY
YYY
ZZ
ZZ

is there any way I can create a column which combines column A with a number 1-4 and apply this number to the value in column A? The result would be:

XXX1
XXX2
XXX3
YYY1
YYY2
YYY3
YYY4
ZZ1
ZZ2

Thoughts?

assuming your data starts in A1, in B1:
=A1 & countif($A$1:A1,"="&A1)