Recessions tend to drive people to entrepreneurship. Those who might never consider starting a business will do so if they can’t get a job. As the United States economy gets stronger, a smaller percentage of the population is starting businesses, according to the Kauffman Foundation’s Index of Entrepreneurial Activity, released recently. Last year, .28 percent of American adults started their own businesses each month, compared to .30 percent in 2012. That means the percentage of startup founders declined from 300 out of 100,000 adults to 280 out of 100,000.