http://www.smartcitymemphis.com/2010/02/new-heroes-entrepreneurs-our-economy-and-our-culture/
Here are the quick hit facts in the article as a teaser:
Fact 1: Over the past 30 years, young companies have accounted for a massive amount of all net jobs (more than two-thirds).
Fact 2: Each young company creates an average of 4 jobs every year.
Fact 3: Since 1977, without startup companies, net job creation for the American economy would be negative in all but a handful of years (meaning we would have lost more jobs than we created over the past 30+ years).