There’s an old joke about things God doesn’t know:
- How many congregations of religious women are there?
- How much money do the Franciscans have stashed away?
- What are the Jesuits going to do next?
So I’m not sure you’re going to find a good answer.
CARA (Center for Applied Research in the Apostolate) gives some numbers for the US for 2008:
Religious priests: 12,966
Religious brothers: 5,001
Religious sisters: 59,208
(And I just realized you asked about the number of congregations, not the number of members. Ah well, maybe someone else will have a number.)