Hey Vaishnavi,
This is an excellent question. But business school don't publish data in that category and I assume you've already checked that. Moreover, European schools boast 80-90% international students because a student from Germany is will considered international for INSEAD - Paris. But even then I make a clear inference that European schools have higher % of employment rates as compared to US schools.
Does this really help? No! Because you've I think looking for figures of Indian students' employment rates which is not available anywhere. So many factors affect employment statistics.
1. Candidates looking for jobs
2. Country's economic situation
3. Country's work permit policies
4. Which industry/ function a candidate is looking for in a job?
I'm not sure if this helps but you've asked a question that often even I think about. Let me know if you find any answers to it.
Good Luck!