The ONDCP recently reported that Mexican drug trafficking organizations make about $13.8 billion a year selling drugs to Americans, close to $8.6 billion from marijuana alone.
http://www.usatoday.com/news/topstories/2008-02-21-2221217072_x.htm
http://pushingback.com/blogs/pushing_back/archive/2008/02/25/40553.aspx
ONDCP estimated the annual mj consumption in the US to be just over a thousand metric tons. It seems to me that either consumption estimates are way too low, or production figures are way too high, or there is a massive glut.
--briancbennett.com/charts/fed-data/consumption.htm