ICANN has published their audit of Registrar compliance with the RAA  Registrar Accreditation Agreement.

19 registrars were found to have non working websites
20 registrars were found to not have a WHOIS service available on their websites.

from a total of 881 accreditted registars.
Over 50% of the failing registars were based in North America.

Registrars which failed the audit will now have chance to rectify the situation, faliure to do so will result in being sent formal notices.  ICANN report