Making it on the list of 100 Fastest Growing Private Companies in Los Angeles County is hard enough to do once. Doing it multiple times is truly impressive.

Nonetheless, one local firm, Woodland Hills’ Account Control Technology Inc., which provides business back-office services, has appeared on the list eight consecutive years. Its revenue jumped to $209.7 million last year from $8.1 million in 2008 – although some of last year’s bump was due to an acquisition. At No. 18, it’s the highest-ranked company on this year’s list that isn’t making its debut.

Fellow Woodland Hills firm BlackLine, which makes cloud-based software for finance controls and automation, is making its seventh-straight appearance. The company’s revenue has gone from $1 million in 2009 to $56.6 million last year, growing at a rate of 615 percent annually.

There are four local businesses appearing on the list for the fifth-consecutive time: Valencia Web design and Internet marketing firm Scorpion Design, North Hollywood cloud computing and IT consulting company Sada Systems Inc., Hermosa Beach telecom consulting firm Sandler Partners and Torrance environmental consulting company Partner Engineering and Science Inc. Downtown’s Sky Zone Indoor Trampoline Park has grown the most of all businesses that have appeared on the list at least four times. The indoor playground company has averaged annual growth of 700 percent.

– Matt Pressberg