Count and Number The Amount of Times That a Unique Value Appears in Increments of One

Hi All,

I'm facing a challenge in Excel that I can't seem to get my head around.

I would need a formula that can look at how many times a value appears in a column and assign a numerical value that goes up by one for each time the value reappears.

For example, if column A contains the value G01029 on five back-to-back rows, column B should give me values: 1,2,3,4,5. If column A contains the value G01030 twice, the corresponding result in column B for these values should be 1,2.

I've attached a sample document. The real file contains about 20,000 rows of data.

Your help is greatly appreciated!