Forty-two states ranked by the average cost to insurers of 162 common medical services in 2015. Includes the ratio of the state average to the national average and examples of average costs of knee replacement, pregnancy ultrasound and cataract removal. Sources: Claims data from the Health Care Cost Institute and from Guroo.com, analyzed by David Newman, Stephen T. Parente, Eric Barrette and Kevin Kennedy, in âPrices for Common Medical Services Vary Substantially Among the Commercially Insured,â Health Affairs, Vol. 35, No. 5 (2016)., Modern Healthcare reporting. Published May 2, 2016, p. 34.