Final answer:
The steady increase in federal government expenditures since 1960 can be attributed to increases in entitlement programs, such as Medicare and Medicaid.
Step-by-step explanation:
The steady increase in federal government expenditures since 1960 can be primarily attributed to increases in entitlement programs, such as Medicare and Medicaid. These healthcare programs have experienced significant growth as a percent of GDP, leading to higher government spending. For example, payments for senior citizens (Medicare) and low-income Americans (Medicaid) have contributed to the overall rise in federal spending. Additionally, Social Security and interest payments on government debt have also played a role in the increase in government expenditures.