Budget, 2020

This graph is from the CBO, which makes its projections based solely on current law.

For context, here's the spending breakdown for some of the big-ticket items in 2009, based on the numbers in this CBO report:

 
  • Defense, 18%
  • Social Security, 18%
  • Medicare, 12%
  • Medicaid, 7%
  • Interest, 5%

Hat tip: Mankiw