displaying an unique number

Hello,
I am using Excel 2007 and have a column of depths from the ship to the seabed with 1m intervals, sometimes I have more than one reading of the same depth. (See below I want to be able to automatically delete values that appear more than once. Like below I want to delete 2 of the 7m's and one of the 8m's so I leave an unique depth. Is there any way of doing this in Excel?? the column is long goes down to 100m

5m
6m
7m
7m
7m
8m
8m
9m...

thanks for your help