If you want to know the answer to this question and access other valuable data related to the U.S. spa industry, then the ISPA 2012 U.S. Spa Industry Study is the resource you need. ISPA members receive complimentary digital access to the entire study, so download your copy today. Not an ISPA member but want to access the ISPA U.S. Spa Industry Study and other valuable research? Purchase a digital copy or become an ISPA member and receive your complimentary download.