Between now and 2015, the shortage of U.S. doctors across all specialties will quadruple to nearly 63,000, according to a report from the Association of American Medical Colleges (AAMC) Center for Workforce Studies.

While previous projections showed a baseline shortage of 39,600 doctors in 2015, AAMC estimated 62,900, with a worsening shortage of 130,600 by 2025. Partially driving the shortage, the U.S. Census Bureau projected a 36 percent growth in the number of Americans over age 65, and nearly one-third of all physicians are expected to retire in the next decade, the report found.

“The shortfall in the number of physicians will affect everyone, but the impact will be most severe on vulnerable and underserved populations,” the report stated. “These groups include approximately 20 percent of Americans who live in rural or inner-city locations designated as health professional shortage areas.”

There also will be a substantial shortage of non-primary care specialists, according to the report. In 2015, the U.S. will face a shortage of 33,100 physicians in specialties such as cardiology, oncology and emergency medicine. In 2025, AAMC estimated that number to rise to 64,800.

“The U.S. already was struggling with a critical physician shortage and the problem will only be exacerbated as 32 million Americans acquire healthcare coverage, and an additional 36 million people enter Medicare,” the report stated.

Increasing graduate medical education by eliminating the 13-year freeze in Medicare’s support for training positions is essential to address the expected shortfall, the report stated. The number of medical school students continues to increase, adding 7,000 graduates every year over the next decade.

“Unless Congress supports at least a 15 percent increase in residency training slots (adding another 4,000 physicians a year to the pipeline), access to healthcare will be out of reach for many Americans,” the report concluded.

Read the report in its entirety here.