MS Access Mark Duplicates in order of appearance
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I am fairly new to MS Access and I need to figure out the best way to mark duplicate instances of a value a new column in ascending order. I have written a script in python that accomplishes this in ArcGIS but I need to figure it out for access. I have a FIELDS Column with the names I want to check for duplicates and a DUP_COUNT column I want to have populated with the number of times a value has occurred.  So the first instance would be designated 1 the second 2 and so forth. I tried doing something similar in MS Excel and I figured out how to mark the first occurrence of a value but not proceeding ones.
=IF(COUNTIF(A:A,A2)>1,IF(COUNTIF(A$2:A2,A2)=1,"1","2"),"")

Example:

FIELDS        DUP_COUNT

Smith              1

Smith              2

Smith              3

Smith              4

Brown              1

Brown              2

Any help would be greatly appreciated!