From 2002 to 2012, between 30% and 40% of U.S. adults ...

...  used complementary health approaches in a given year. The percentage of those who had at least some health insurance coverage for their complementary approaches was:

• 60% of those seeing a practitioner for chiropractic
• 25% of those seeing a practitioner for acupuncture
• 15% of those seeing a practitioner for massage therapy

Source: "Insurance Coverage for Complementary Health Approaches Among Adult Users: United States, 2002 and 2012," Centers for Disease Control and Prevention, NCHS Data Brief No. 235, January 2016, http://www.cdc.gov/nchs/data/databriefs/db235.htm