This is the Business Journal’s 20th annual list of the 100 fastest growing private companies in Los Angeles County. It was tougher than ever to make the cut this year, as more companies saw huge growth.

More than 250 companies completed surveys for the list, which ranks businesses on their two-year revenue increase.

Among respondents, 54 reported a two-year growth rate of 100 percent or more. That’s the most to have doubled revenue within two years, surpassing the 53 companies that reported that growth level between 2005 and 2007.

In addition, the top five companies on this year’s list each saw revenue increase by more than 1,000 percent. In the ranking’s 20-year history, no list has had more than two companies achieved that level of growth.

Fourteen companies surpassed 500 percent growth, also the most to achieve that over the past 20 years. Only seven companies reported 500 percent growth last year.

To qualify for the list, a company must have 2013 revenue of at least $5 million, be headquartered in Los Angeles County and may not be a subsidiary or division of another company. Companies must provide three full years of revenue: 2011, 2012 and 2013.

The Business Journal calculates the percentage increase in revenue from 2011 to 2013.

Very few companies are able to sustain rapid growth for more than three years, and of the companies listed, only 10 have been included on four or more consecutive lists. One company, Account Control Technology Inc. in Woodland Hills, has appeared on the list for seven consecutive years. Its revenue has climbed to $78.7 million last year from $8.1 million in 2005.

– David Nusbaum