Figure 5.7 on page 167 shows that the Congressional Budget Office forecasts that less than half of future increases in spending on Medicare and Medicaid as a percentage of GDP will be due to the aging...

Figure 5.7 on page 167 shows that the Congressional

Budget Office forecasts that less than half of future

increases in spending on Medicare and Medicaid as a percentage of GDP will be due to the aging of the population.

What factors explain most of the increase?