State table - Should I use the State Abbreviation or a Autonumber for the Primary Key?

[adibakale]

I have a Customers table that holds a customer account number, Customer name, Street, City, State, Zip.

I want to make a lookup table for City and a lookup table for State.

Should I use the State Abbreviation for the Primary Key or an Autonumber?

 

[Aladin Akyurek]

If the space of entries are finite (not growing) and the state abbreviation are unique, State Abbreviation as primary key would be appropriate, otherwise AutoNumber.