The WHI study recruited postmenopausal women in the 50-79 age range, and sought to be as inclusive as practical. The wide nature of the age range balanced the need to observe the effects of hormone therapy on younger women, while also attempting to capture physical and cognitive outcomes in older populations. In addition, a 20% minority enrollment rate was set for all components, to accurately represent the proportion of minorities within the study demographic (17% at the time of the 1990 U.S. Census). To achieve this, 10 of the 40 WHI clinical centers were designated as minority recruitment centers, with enhanced minority recruitment goals.