I have a simple list, the left column is the customer number, the right
column is the date of every sale made to the customer. I need to filter this
list to show the most recent date only for each customer. The list has many
hundreds of customer numbers with between 1 and 200 dates per customer.
There are no blanks in the list

eg.
1234 25/10/2009
1234 26/10/2009
1234 03/03/2010
1356 23/12/2009
1356 25/04/2010
1999 06/02/2009
2157 09/05/2009
2157 10/06/2009
2157 25/11/2009
2157 23/04/2010

result would be
1234 03/03/2010
1356 25/04/2010
1999 06/02/2009
2157 23/04/2010