SME’s made up 97.6% of all US exporters- 269,269 SME’s (businesses employing fewer than 500 workers) exported from the USA in 2009 (latest data available).
Known export revenue of these SME’s- $308.0 billion– that’s ~32.8% of goods exports.

By the way, SME's also need access to capital.

SME’s accounted for 97.1 % of identified importers in 2009; 174,612 SME’s reported imports.
Current Export Situation
According to March 2011 U.S. International Trade in Goods and Services report, U.S. exports of goods and services increased by 4.6%  in March 2011 to a record $172.7 billion since February 2011.
The record was made up of record exports of goods ($124.9 billion) and services ($47.7 billion).
What about the Delta?
The monthly increase in export value (delta or difference)  for goods and services between February and March 2011 was $7.7 billion, also the highest monthly change (delta) on record.
Optimistic Bottom Line: U.S. goods and services exports in the first quarter of 2011 are up 14.9% to $505.2 billion from the $439.6 billion in exports logged in first quarter 2010.
Pessimistic Bottom Line: U.S. Imports of goods and services increased as well,  4.9% over this period, to $220.8 billion.
Result- U.S. Trade Deficit increased by 6.0% since February 2011 to reach $48.2 billion March 2011.
Imagine what the U.S. Trade Deficit would be if the SME’s hadn’t stepped up in March…
Photo credit:  Umpqua Bank  (Really a neat story here- check it out.)
Data: U.S. Export Fact Sheet March 2011