I'm pretty sure you're correct and those numbers are total since 1950. However, the study does seem confusingly worded - in the footnote on page 1 it says:
"All estimates quoted are in constant 2010 dollars, unless otherwise noted, and refer to actual expenditures in the relevant fiscal year, rounded to the nearest billion"
At least to me that reads like "all estimates refer to expenditures from the relevant fiscal year only". However, they later quote the same numbers as being "total spending since 1950". Am I just missing an obvious interpretation for the footnote?
I think you are. I interpret that as the estimates for each year are quoted in 2010 dollars unless noted and that those estimates (that is, the ones for each year) refer to actuals in each of those years. Then they are summed to produce the $600b.
"from the relevant fiscal year" implies that each value relates to a corresponding fiscal year. Your addition of 'only' is redundant.
But the estimates the footnote is referring to are in the first table. Those are not per year but already summed; there's no corresponding fiscal year to refer to (I think?).
Regardless, this is a tiny point so I'll drop it. I still feel confused though :(
"All estimates quoted are in constant 2010 dollars, unless otherwise noted, and refer to actual expenditures in the relevant fiscal year, rounded to the nearest billion"
At least to me that reads like "all estimates refer to expenditures from the relevant fiscal year only". However, they later quote the same numbers as being "total spending since 1950". Am I just missing an obvious interpretation for the footnote?