Counting duplicates in Excel

Question

I have a list of postcodes that includes duplicates. I would like to find out how many instances of each postcode there are.

For example I would like this:

Answer 1

Step 1: Select top cell of the data

Step 2 : Select Data > Sort.

Step 3 : Select Data >Subtotal

Step 4 : Change use function to "count" and click OK.

Step 5 : Collapse to 2