Assigning Unique ID

Hi All-

I have a 13k row spreadsheet that I need to assign a unique ID to each client to import into a database. There are many repeat clients in the spreadsheet that need to have the same ID. The only fields in the spreadsheet are first name, last name, address1, address2, city, state, zip, phone#, fax#. Does anyone know a way that I assign a unique ID to the client based on the fields I have available to identify each unique client.

Thanks in advance

ClikClak