When trying to count the number of same values in one column Excel does count
a number of these, but then gives only zero to answer value.

It is like this:

column A column B


11.11.2002 0:01:00 11.11.2002 0:01:00
11.11.2002 0:01:00 11.11.2002 0:02:00
11.11.2002 0:02:00
11.11.2002 0:03:00
etc.

column C

=COUNTIF($A$1:$A$lastvalue;B1)
=COUNTIF($A$1:$A$lastvalue;B2)
etc.

On count 1 answer should be 2 (there is 2 times cell matching cell B1)
On count 2 answer should be 1 (there is 1 times cell matching cell B2) etc.

But Excel (version 2002 SP3) does this randomly and gives answers mostly
zero when copying the function in column C down. What to do ?

Thanks, TT