Adding line numbers within a group

I have a table in this format:

Bob 5
Bob 6
Bob 19
Alice 3
Alice 26
Alice 0
Alice 8
Alice 8
Cory 3
Cory 6

I want to add line numbers that restart for each name, ie.

Bob 5 1
Bob 6 2
Bob 19 3
Alice 3 1
Alice 26 2
Alice 0 3
Alice 8 4
Alice 8 5
Cory 3 1
Cory 6 2

Any ideas how I would do this?

Thank you.

Insert a blank row 1 if you don't have anything above your first Bob, then in C2 you can have this formula:

=IF(A2<>A1,1,A1+1)

then copy down.

Hope this helps.

Pete

Thank you all! COUNTIF worked.