To allow anyone to easily investigate and compare trends in government military expenditure, I took data from the Stockholm International Peace Research Institute, and built five online interactive visualization tools. Here they are, make use:
Total Military Expenditure (constant 2011 $)
Bonus fun material: Correlated Spenders.
Go ahead and do your own plotting.
A word of thanks to the SIPRI, and specifically to the staff at their Military Expenditure Database Program who (1) collect the data that made all of this possible and, (2) gave me useful feedback on this work when I shared it with them.