Puerto Rico's central government, which includes all three branches of government but excludes public corporations and municipalities, has an annual general budget that currently ranges from $8.5 billion to $9 billion in revenues and expenditures. The government also receives more than $4.2 billion annually in subsidies and federal aid from the United States. A substantial portion of this amount is earmarked for public welfare, including funding educational programs (such as Head Start), subsidized housing programs (such as (Section 8 and public housing projects), and a food stamp system called the Nutrition Assistance for Puerto Rico program.