Washington ? The economy has cranked out fewer jobs under President Bush – by millions – than it had by the same point in the presidencies of Ronald Reagan and Bill Clinton.

Democrats say it’s evidence that Bush’s economic policies aren’t working.

Commerce Secretary Carlos Gutierrez counters, in an interview, “It’s just a matter of timing and when we started getting out of the recession that the president inherited.”

Economists suggest something fundamentally different also may be going on in the economy: The labor force of available workers is growing more slowly as the baby boom generation ages.

Under Bush, the economy produced 3.7 million new jobs from January 2001 through December of last year based on nonfarm payroll figures collected by the Labor Department’s Bureau of Labor Statistics.

That figure is likely to be higher – perhaps by an additional 810,000- when the government releases annual revisions based on more complete information next month. However, that doesn’t change the basic historical picture.

When Clinton was in the White House, the economy generated 17.6 million jobs during the corresponding period – from January 1993 to December 1998. Under Reagan, 9.5 million jobs were created from January 1981 to December 1986.

Those are the two most-recent two-term presidents before Bush. Some 2.6 million jobs were created during the four-year term of Bush’s father, who took office in January 1989.

Reagan had two recessions – one of which began in July 1981 and ended in November 1982. It was the most severe recession since the Great Depression, pushing the monthly unemployment rate as high as 10.8 percent.

Bush, too, has had his economic challenges. He had the 2001 recession and that year’s terror attack. And, Gutierrez noted, Bush faced lingering fallout from the bursting of the stock market bubble in 2000. He also was confronted with a wave of corporate accounting scandals that rocked Wall Street – and with Iraq war beginning in 2003.

The economy lost jobs in 2001 and 2002. Since then jobs have been growing each year – including 2006, when the economy was hit by the real-estate bust.

Those jolts did affect jobs on Bush’s watch, economists say. Yet they see deeper reasons for slower job growth, too.

Baby boomers – a huge block of workers – poured into the work force in the 1980s and were rising through the ranks in the 1990s. That’s not the case now as boomers face retirement, and there are fewer young people to take their places.

Women, meanwhile, who helped to bulk up the labor force over the past few decades aren’t streaming into jobs as they once did.

These changing demographic factors will shape the country’s future.

“The impending retirement of the baby boomers and the fact that women are no longer increasing their participation in the labor force at the rate they were in the past will tend to restrain the future growth of the U.S. labor force,” Federal Reserve Chairman Ben Bernanke said in a major speech on the economy’s outlook in late November.