How to do Kendall test with ordinal data

#1
Hi,

I have the following profitability data:

1) Rankings of profitability for customers: 1, 2. ... 15

2) Categories of same customers, grouped after profitability (from 1 to 5):
5, 5, 5, 3, 4, 5, .... 5, 4 (15 in total)


I have troubles finding the Kendall Tau (correlation) for these groups, as data set (2) is ordinal. Please suggest solutions or links.