This question already has an answer here:
Pursuant to this question from a year ago, can we define a migration list for our site?
As of Aug.24,2012 - the migration stats for the past 90 days:
- Cryptography with 16 migrations
- ServerFault with 6 migrations
- SuperUser with 5 migrations
- Stack Overflow with 4 migrations.
This does not include Meta.Sec.se, a bunch of sites with a single export, and does not take into account rejections from the target site.