Deleting the data and compacting the data should reset them. However, what
does it matter? The only point for an AutoNumber field is to provide a
(practically guaranteed) unique value that can be used as a primary key.
346467, 346468, 346470 serves that purpose just as well as 1, 2, 4 does.
Seldom, if ever, should your users even be aware of the AutoNumber value.
