A new Global Entrepreneurship Monitor (GEM) report surveys the entrepreneurial lifecycle in the United States. Drawing on 2008 data, What Entrepreneurs Are Up To looks at who starts a business and why, how start-ups begin, and the impact of public policy. There is also a chapter comparing the activity, attitudes, and aspirations of U.S. entrepreneurs with their counterparts in other countries.

A few key findings:

1. Opportunity, not necessity, is a prime driver—especially for men. The survey found that only 5 percent of men start businesses out of necessity; for women, that number climbs to 21 percent.

2. Entrepreneurs are skewing older, with an 8-9 percent increase in entrepreneurial activity among people 45 and older (and a commensurate drop in entrepreneurial activity  among those 18-44).

3. Men have far better access to capital. GEM found that “women start ventures with eight-times less funding than their male counterparts.”

4. Men typically start “business-service businesses”; women, consumer-oriented businesses.

5. African-Americans have the highest level of start-up activity (13.9 percent versus 8.4 percent for whites and 8.6 percent for non-Mexican Hispanics).

6. Social entrepreneurship is being largely driven by women, and is focused in the areas of health care, education, urban development, and the environment.

The report is packed with data, and I’ve just scratched the surface here.