In 2017 net interest comprised 6.6 percent of total budget outlays, the budget projects it will be 8.2 percent of total outlays in 2019 and 12.2 percent of total outlays in 2028.
Comparing net interest to the size of the total discretionary budget outlays, in 2017 net interest was 21.9 percent as large as the discretionary budget, in 2019 the budget estimates it will be 27.8 percent the size of the discretionary budget. The Trump budget estimates that in 2028 net interest will be 62.4 percent as large as the discretionary budget. (That’s both defense and non-defense.)
We often talk about the exploding growth in mandatory programs – the budget estimates they will grow by 70 percent between 2017 and 2028. Net interest is set to grow 189 percent over the same period.
This bar chart sums up the situation nicely…