For years Red Hat security hawk Mark Cox has released risk reports on Red Hat Enterprise Linux security numbers and response times. Today brought the latest. This report encompasses the security issues addressed in Red Hat Enterprise Server since the release of 6.1 six months ago.
Cox reported that a total of 88 advisories addressed 218 vulnerabilities. Out of those 10 advisories addressing 31 vulnerabilities were rated critical. Cox also reported that "Updates to correct all of the 31 critical vulnerabilities were available via Red Hat Network either the same day or the next calendar day after the issues were public."

Back in May Cox issued his report on 6.0 through 6.1. For that version 102 advisories were shipped to address 345 vulnerabilities. 8 of these were critical and all 37 of the covered vulnerabilities were addressed the same or following day.
See the full report for more details.