Birmingham's economy is largely driven by the healthcare sector, with top employers such as the UAB Health System, Baptist Health System, and St. Vincent's Health System, whose hospitals and clinics are expected to change their name to Ascension. The name change is part of a greater effort to coordinate healthcare efforts across the entire Ascension system, which is the largest chain of Catholic hospitals in the world. The UAB Healthcare System is also undergoing some changes. U.S. News & World Report's top ranked hospital in Alabama added seven operating rooms to the Callahan Eye Hospital in April 2017, while in August 2017, a new, 60,000-square-foot expansion of the John N. Whitaker Building opened. Known as the Whitaker Clinic, the new facility includes primary care, dermatology, podiatry, and rheumatology clinics. Additionally, the Ronald McDonald House Charities of Alabama's three-story, 28,543-square-foot addition opened in January 2018. The healthcare sector is the largest demand driver for hotels in and around Downtown Birmingham, with year-round demand driven by patients, relatives of patients, doctors, and pharmaceutical sales representatives.