How to count duplicate values in a CSV column compared to total rows using Excel?

I have a csv file with many thousands of rows. One of the columns has duplicate values. I want to be able to see how many duplicates are there compared to the total rows - so x,000 duplicates from y,000 total . I can do this in xl by selecting the column, data/filter, Home/conditional formatting). After that/Highlight Cell Rules/Duplicate Values, from New Formatting rule select OK (Format with light red fill etc(. Then select the column dropdown, followed by Filter by color / Cell color/no fill).

This results in the total of no fill entries - i.e. without the duplicates included.

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