Dane Stangler and Paul Kedrosky--senior analyst and senior fellow, respectively, at the Ewing Marion Kauffman Foundation--have put together a comprehensive paper on the number of companies started in the U.S. year over year.  They find the number surprisingly consistent.  Here's a look at the numbers from the Census Bureau:

The data does not include our recent global recession, but it is striking to be sure.  The Stangler and Kedrosky examine several possible explanations in this early study of the data.  But the numbers available do seem to back up the notion that the U.S. is a highly entrepreneurial country.

It remains to be seen, too, how the severe recession of 2007 09 will affect new-firm formation in the United States. Early indicators are mixed, with some showing a rise in entrepreneurship and others showing a decline. Nevertheless, it's clear from the evidence presented here that entrepreneurship the creation of new firms and the jobs and innovations they bring is a persistent phenomenon in the United States economy. At any given time, hundreds of thousands of Americans are prepared to take a leap into the unknown and pursue an idea. Policies will affect this number at the margins, but the most important thing we can do to promote entrepreneurship is to provide a hospitable environment. Entrepreneurs are the bearers of often-discomfiting change and we must continue to ensure that such change is not prospectively discouraged, but welcomed and celebrated.

Read EXPLORING FIRM FORMATION: WHY IS THE NUMBER OF NEW FIRMS CONSTANT? here.