The International SPA Association (ISPA) has released its annual findings of US spa industry financial indicators, reporting the industry continues to grow as it surpassed the US$15bn (€13.3bn, £9.7bn) mark.

The ISPA Foundation commissioned PricewaterhouseCoopers (PwC) to conduct the study, which presents what is known as the United States spa industry's “Big Five”: total revenue, spa visits, spa locations, revenue per visit and number of employees.

“It is always an exciting time to reveal the Big Five, as these numbers are strong indicators of the future success and growth of the spa industry,” said ISPA president Lynne McNees. “As ISPA celebrates its 25th anniversary, we are proud to report this milestone for the spa industry.”

Total revenue passed the US$15bn mark in 2014, up from US$14.7bn in 2013 to US$15.5bn in 2014, a 5.3 per cent increase.

ISPA said the increase in spa revenues was driven by strong growth in the number of spa visits, estimated to have increased to a record high of US$176m in 2014, up from US$164m in 2013, a 6.7 per cent increase. As the increase in visits outpaced the rise in spa revenues, there was a slight 1.3 per cent decline in average revenue per visit, from US$89 in 2013 to US$88 in 2014.

The total number of spa locations rose from 20,180 in 2013 to 20,660 in 2014, a 2.4 per cent increase. Total employment is estimated to have risen to 360,000 as of May 2015, an increase of more than 10,000 on the May 2014 position and a 2.9 per cent gain.

"This year's study highlights the strong performance in total revenue and number of spa visits,” said Colin McIlheney, global research director for PwC. “The growth in these areas shows the US spa industry is buoyant and building on the momentum established in the previous year.”

The complete study will be released in late September 2015.