(Editor's Note: For the latest list, the 2015 Club Industry's Top 100 Clubs list, click here.)

Several familiar club companies are on Club Industry's Top 100 Clubs list this year. A few of those companies are just not as familiar to the list itself.

The top company on this year's Top 100 Clubs list is LA Fitness, repeating its top ranking from last year when Club Industry estimated the company's 2012 revenue at $1.7 billion. This year, using an estimate from Moody's Investor Service, we list the Irvine, CA-based company at $1.7 billion in 2013 revenue. LA Fitness had 619 clubs at the end of 2013.

24 Hour Fitness, San Ramon, CA, is No. 2 on the Top 100 Clubs list, also for the second year in a row. Last year, Club Industry estimated 24 Hour Fitness at $1.5 billion in 2012 revenue. This year, using a Moody's estimate, 24 Hour Fitness is listed with $1.3 billion in 2013 revenue. 24 Hour Fitness did report to Club Industry that it had 413 clubs at the end of 2013. Earlier this year, Forstmann Little and Co. sold 24 Hour Fitness for a reported $1.85 billion.

Moody's also estimated revenue for Equinox, which helped put the New York-based company back on the Top 100 Clubs list after a four-year absence. But other sources helped us get Gold's Gym and Curves on the list, too. Club Industry relied on independent outside sources to estimate revenue for Gold's Gym, which has been private about its revenue information for many years. The Curves estimated revenue was taken from an article published earlier this year by Forbes. Even though some companies chose once again not to submit revenue information to Club Industry, with some of the well-known brands added this year, the Top 100 Clubs list is as inclusive as it has ever been.

Moody's estimated Equinox's revenue at $740 million as of March 31, 2014, putting Equinox at No. 5 on the list. Although the Top 100 Clubs list is based on figures for the year ending 2013, Club Industry made an exception in this case, as this was the most recent revenue estimate available for Equinox, which also operates Pure Yoga, SoulCycle and Blink. Recently, Equinox acquired the Sports Club/LA clubs from Millennium Partners Sports Club Management, Boston, which is No. 14 on this year's Top 100 Clubs list with a reported $99.8 million in 2013 revenue.

Gold's Gym, Dallas, cracks the list at No. 10. Industry sources, which did not have access to Gold's Gym's financial documents, estimated for Club Industry that Gold's Gym had $135 million in 2013 revenue. Gold's Gym reported that it had 661 clubs at the end of 2013.

Club Industry counts only corporate club revenue and revenue derived from franchise fees for franchisors on the list. Other media outlets had different figures for Gold's Gym revenue. Hoover's, a subsidiary of The Dun & Bradstreet Corp., lists Gold's Gym revenue at $80.9 million. InsideView, a software as a service company, listed Gold's Gym revenue at $1.2 billion, but that likely consists of all revenue produced by Gold's Gym corporate and franchised clubs, sources say.

Recently, Gold's Gym acquired all 23 clubs from The Rush Fitness Complex, Knoxville, TN, which is No. 31 on this year's Top 100 Clubs list with a reported $44.8 million in 2013 revenue.

Curves International, Waco, TX, is tied for No. 24 on the Top 100 Clubs list this year with a Forbes estimate of $52 million in 2013 revenue. Curves is operated by private equity firm North Castle Partners, Greenwich, CT, which acquired Curves in 2012. Last year, North Castle and Curves acquired weight management company Jenny Craig and formed a partnership with trainer Jillian Michaels of "The Biggest Loser" fame.

(Rick Caro, president of Management Vision, New York, offers his perspective on the health club industry in 2013 in a sidebar that follows this article.)