American physicians, worried about changes in the health care market, are streaming into salaried jobs with hospitals. Though the shift from private practice has been most pronounced in primary care, specialists are following. Last year, 64 percent of job offers filled through Merritt Hawkins, one of the nation's leading physician placement firms, involved hospital employment, compared with only 11 percent in 2004. The firm anticipates a rise to 75 percent in the next two years. Today, about 60 percent of family doctors and pediatricians, 50 percent of surgeons and 25 percent of surgical subspecialists — such as ophthalmologists and ear, nose and throat surgeons — are employees rather than independent, according to the American Medical Association. "We're seeing it changing fast," said Mark E. Smith, president of Merritt Hawkins.