There were an estimated 2,800 medical clinics in U.S. retail space at the end of 2017, up from just 351 in 2006, according to the report — titled Healthcare: A Growing Force in Retail Real Estate Part I — which cited statistics from consultancy Accenture. Forty-seven percent of that growth occurred in just the three years leading up to year-end 2017.

The number of healthcare clinics in U.S. shopping centers could reach 4,000 by 2020, according to Chad Pinnell, managing director of JLL’s Health Care Solutions group. When it comes to healthcare tenants in general, as opposed to just clinics, about 12,000 of the approximately 116,000 U.S. shopping centers now have them, the report says.

Two demographic groups essential to the growth in U.S. healthcare spending are baby boomers, who spend five times more on medical care than the average patient-consumer; and Millennial women, who are responsible for nearly 80 percent of healthcare decisions for themselves and their families, according to the report.

There are several synergies shared by medical and retail tenants, but also potential challenges, according to Part II of the report. Prescriptions and other patient needs can be fulfilled in nearby stores, and heavy daytime visits to healthcare tenants complement retail parking demand, which peaks from late afternoon to evening. But landlords should be aware of possible issues when it comes to underwriting and negative perceptions about medical facilities on the part of existing retail tenants.