[napscoordinator]

http://tvbythenumbers.zap2it.com/2015/05/21/final-broadcast-of-late-show-with-david-letterman-delivers-largest-audience-since-1994/407030/

Kinda wrong. He had over 13 million. Not sure where those numbers came from that you are giving as fact.

[SamAdams76]

But that was just the last show, which had a curiosity factor. The very article posted here talks about the average audience dropping to 2 million.