By the way, Scientific Linux isn't perfect when it comes to these delays either. I wanted to make a similar graph plotting SL, but laziness prevailed. (I crawled the RHEL, CentOS, and OL mailman archives to get the data, but SL uses listserv.)
It's just one data point, but:
Red Hat released RHEL 5.6 on January 13, 2011, but Scientific Linux didn't release SL 5.6 until June 21, 2011
It's just one data point, but: Red Hat released RHEL 5.6 on January 13, 2011, but Scientific Linux didn't release SL 5.6 until June 21, 2011
[1] https://www.redhat.com/archives/rhelv5-announce/2011-January... [2] http://www.scientificlinux.org/news/sl56