Formula which auto-generates "item #" based on organization value

Background:
- I have an XLS (see attached) that includes various organizations (for illustration purposes only, I depicted as as U.S. States in column C).
- Column A (Item #) has been manually produced. Ultimately, it shows an Item # (in ASC order) for each state.

Specific Examples:
- "CA" shows item # 1, 2
- "FL" shows item # 1, 2, 3, 4
- "IN" shows item # 1, 2, 3, 4, 5, 6
- etc.

Here's what I Need Some Help With:
- I need to have a formula (col B) which mimics the output in column A.
- That is, when I drag down the formula from B2 to B33, it must utilized the values in column C and re-start the counter once a new state is utilized.
- How can this be accomplished in the most efficient way?

Thank you for your help in advance.
Tom

Perfect! Your formula works great!!