Automatically number rows in Crosstab based on Top N sort

I have a crosstab which displays the top 100 clinics, based on number of referrals. Is there a way to add an incremented number to each row which changes dynamically based on which clinics make the "top 100" and their order?

Example:

1 Clinic Z 200 Referrals

2 Clinic B 180 Referrals

3 Clinic A 150 Referrals

Thanks for any help!