The health care industry added 20,000 jobs, construction 13,000. But manufacturing, which includes many higher-paying positions, shed 6,000. The manufacturing sector has weakened this year, in part because struggling economies in Europe and elsewhere have reduced demand for U.S. goods.Many of the new jobs are only part time. The number of Americans who said they were working part time but would prefer full-time work jumped 322,000 to 8.2 million â¿¿ the most in eight months. That could be a sign that some employers are hiring more part-time workers to avoid the health care reform law's requirement that companies provide health coverage to full-time staff. That mandate was to take effect Jan. 1. But this week, the Obama administration postponed it until 2015. The rise in part-time jobs helped boost one measure of weakness in the job market â¿¿ the so-called underemployment rate. This includes not only the unemployed but also people with part-time jobs who want full-time work and people who have stopped looking for work. In June, the underemployment rate rose from 13.8 percent to 14.3 percent. That's still down from 14.8 percent a year ago. The rate peaked at 17.1 percent in April 2010. Jobs have been added at a faster pace this year than the economy's sluggish growth would suggest. The economy expanded at only a 1.8 percent annual rate in the first three months of the year. Most analysts think it grew even more slowly in the April-June quarter. But later this month, the government will revise its estimate of the economy's growth for the first quarter, and many analysts think it will be revised up. They also think the economy will accelerate in the second half of the year. Last month's job growth came solely from the private sector, particularly services firms. Government jobs fell 7,000, mostly at the federal level. The federal government has shed 65,000 jobs in the past 12 months. Some of that decline is due to the spending cuts that kicked in March 1.