Which of the following is true regarding government expenditures in the United States?

a. As a share of GDP, government expenditures were higher in 1950 than 2012.
b. Government expenditures were more than 30 percent of GDP in 1930.
c. Government expenditures as a share of GDP grew rapidly between 1930 and 1980.
d. In 2012, government expenditures at all levels summed to approximately 10 percent of GDP.