Using data from Wolfram Alpha or some other source, replot the NASA graph here http://ripetungi.com/the-rise-and-fall-of-nasas-budget/ either:
1. Controlling for inflation,
2. Tracking expenditure as a percentage of GDP, or
3. Tracking expenditure as a percentage of government spending.
Defend your choice, and note any differences in the shape of the graph that result.