Quick Vegetable Facts:
In 2012, the commercial value of vegetables reported by the USDA was $12 billion of which tomatoes and lettuce each accounted for 15.5% of that value for a combined 31% of the value. Onions accounted for 7.8%.
In 2012, California accounted for 51% of the over $12 billion in US commercial value of vegetables with Florida accounting for 12.5% and Arizona producing approximately 7.2% of that value.
source: http://www.usda.gov/oce/weather/pubs/Other/MWCACP/namerica.htm and http://www.usda.gov/nass/PUBS/TODAYRPT/cpvl0213.pdf