Amid a general decline in company payrolls, the number of jobs for administrative assistants is expected to keep growing over the next decade -- along with their salaries, a government report shows.

More than 4.2 million people were employed as administrative assistants across the United States in 2006, with as many as 362,000 new positions to be added by 2016, according to the Labor Department. With a projected gain in employment of 8.5 percent over 10 years, administrative assistants are expected to see the largest growth of any job category. This year alone, average salaries for admin staff are expected to rise by 3.2 percent.

Industry watchers attribute the gains to an expanding scope of duties and responsibilities.

"As the role of admins expands, so does their value to organizations," Susan Fenner, a professional development manager with the International Association of Administrative Professionals, said in a statement.

Fenner said more employers are filling positions with admin staff that have a range of skills, from coordinating company projects to leading onsite and virtual work teams.