A handful of Orange County companies have made Inc. Magazine’s inaugural list of 100 companies that have added employees at a rapid pace in the U.S in recent years.

Inc.’s Hire Power Awards list measured hiring at privately held, U.S.-based companies from 2008 through 2011. Companies had to have been founded prior to 2008 and had at least 50 full-time U.S.-based employees in 2011.

Santa Ana-based security and janitorial services company Universal Services of America topped the list, with 17,330 new employees over the time span, for a total of 20,760. About 2,000 employees are in Orange County. Some of Universal Services gains are tied to acquisitions. The company has made five acquisitions so far this year, with more deals expected to close before the year-end, according to Co-Chief Executive Steve Jones.

Pacific Dental Services Inc. in Irvine ranked No. 4, having added 1,451 jobs for a total of 3,422.

No. 17 Rancho Santa Margarita-based Applied Medical Resources Corp. has added 782 jobs over the years, reaching nearly 2,000 employees.

Irvine-based dental services provider Smile Brands Group Inc. made the list at No. 31, after adding 551 workers for a total of 4,483 employees.

Tustin-based mortgage banker New American Funding was No. 86. It has added 267 jobs, growing its employee base by more than five times to 331. The company is in the process of expanding from OC into the San Diego market.

The 100 companies on Inc. Magazine’s list have collectively created 73,032 jobs over the time period. About 46% of the total was from the top 10 companies.

The list included four companies with 2011 revenues larger than $1 billion and six firms with revenues between $500 million and $1 billion. Those with sales between $100 million and $500 million made up about a third of the list, and companies that posted less than $100 million last year accounted for more than half the list.