I have a worksheet with 2 columns of data (non-numeric), I need to count the
occurences of each row in column 2 in column 1. The data in column 2 appears
once and in column one it may appear 1-many times. eg data is like this,
(column 3 is the requested count of column 2 in column 1)

abc abc 1
abcd abcd 2
abcd acd 3
acd ...
acd
acd
...

There's 10,000 rows in column 1 and 3000 rows in column 2