Are all broadcast programs closed captioned? Unfortunately, no but in a recent ruling new FCC regulations require 95% of all new programming to be captioned with eight years as of January 1, 1998.
Source:
http://www.wzzm13.com/faq.aspx#eight
Another good article
DTV: Closed Captioning in a Digital Age can be found here
DTV: Closed Captioning in a Digital Age