Someone forwarded a link to the recent FTC report on the Do-Not-Call list.  It was required to prepare a progress report on the accuracy and efficacy of the list as part of the Do-Not-Call Improvement Act of 2007.  (Link here, list here [pdf].)

The list has a few interesting facts, such as: as of July 31, 2008, there were 168 million numbers registered. 

The bulk of the report is devoted to determining the accuracy of the list and means of improving the accuracy.  The DMA argued that a slew of numbers should have been removed from the list.  Unfortunately for the DMA, its numbers were pretty far off ("[the] DMA's contractor refined its scrubbing process to tighten the definition of reassigned numbers and re-analyzed the numbers it had submitted to DMA . . . [u]sing its refined scrubbing process, the contractor determined that close to 42% . . . should still be treated as active registrations . . . .").

The report contains scant discussion of the accuracy of the list vis a vis mobile numbers, since mobile carriers are not required to provide information to the National Directory Assistance database regarding disconnected or reconnected numbers.  The starting point for purging numbers is the NDA database. 

Also missing from the report:  any real penalties for companies who call you anyway, notwithstanding the presence of your number on the list.