Sequentially Count Duplicates In List

I am trying to work out how I can assign a sequential value to sets of duplicate data within a list. i.e. where I have duplicates in a list I want each of the duplicates (that are in the same set) to have a sequential number assigned and for that to start from 1 each time it discovers a new set of duplicates.

RED
GREEN
YELLOW
PURPLE
RED
ORANGE
BLACK
GREEN
RED

Where a colour is duplicated in the list I want it to have a sequential number assigned. When a new set of duplicates is found the numbering starts from 1 and sequentially increases. So the above data list would resulting in the following output

RED 1
GREEN 1
YELLOW
PURPLE
RED 2
ORANGE
BLACK
GREEN 2
RED 3

Have tried variations of the RANK function, but not sure how to get the sequential nu,bering to restart with each unique set of duplicates. I would also like to do this without VBA if possible using the built in functions.