Hmmm... You're number $30B actually seems really low. A quick Google shows this from the census bureau: http://www.census.gov/mrts/www/data/html/06Q3.html htt

Hmmm... You're number $30B actually seems really low. A quick Google shows this from the census bureau: http://www.census.gov/mrts/www/data/html/06Q3.html http://www.census.gov/mrts/www/data/html/06Q3.html |Total retail sales for the third quarter of 2006 were estimated at $991.7 billion, an increase of 0.7 percent (X0.3%) from the second quarter of 2006. so, assuming that sales are close to $900 billion per quarter, I think that we can safely say that retail sales probably do business in the 2-4 trillions of dollars per year.