The Congressional Budget Office (CBO) makes 10-year and long-term budget projections for the United States government, including projections of federal spending on major health care programs. CBO projections serve as a benchmark for measuring the fiscal impact of proposed policy changes. Federal spending on Medicare, Medicaid, the Children's Health Insurance Program, and Affordable Care Act exchange subsidies is projected to increase significantly as a share of GDP over the next 25 years due to growth in health care costs and the aging of the population. CBO examines options for reducing the growth of federal health care spending through various reforms to programs, provider payments, and the overall health care system.