It's the single largest source of such funding in the US (and I imagine in the world, too), yes. I don't know that it's >50% though, but it's certainly a large

It's the single largest source of such funding in the US (and I imagine in the world, too), yes. I don't know that it's >50% though, but it's certainly a large fraction. For example, it's budget is 4 times that of the NSF or CDC.