During the Past Few Decades, the Percentage of Our Income

During the past few decades, the percentage of our income spent on health care:

A) has increased due to an aging U.S. population.
B) has decreased due to advances in medical technology.
C) has increased due to advanced demand-and-supply distribution of health care facilities.
D) has decreased due to increased regulation and decreased administrative costs.
E) has decreased due to the reduction in health care costs.