These numbers were on the title card at the very end of the last episode.
243 addicts were filmed.
238 went to treatment.
156 are sober today.
That means 64% of addicts on the show were sober as of July 2013.
13 addicts (that we know of) have died since their intervention, as of Aug 2014.
12 of those 13 addicts went to treatment (Sean did not).
At least 3 of those addicts, possibly more, had successful interventions and were sober/ in recovery at the time of their death (Bret, Sandy, and Mike. Not sure about Jackie, Sebastian, or John).
The 5 who did not go to treatment: Alissa, Marquel, Larry, Adam, Sean.