Source: WEO, IMF
Nothing earth shattering. Just the size of the average government spending as a share of GDP between 2001 and 2015 in a few developed countries, all of which, but one, have comprehensive health coverage. So it's reasonable to assume that if the US wanted that (healthcare for all), it would have to increase spending to something closer to 40% of GDP, for all levels of government, rather than the current 35% or so. Nothing implausible about that (wink, wink, nudge, nudge, say no more).