100 %. But wait....if that's true than we'd all be dead. Unless we are already dead and we are just in a different dimension, or perhaps we are all hooked up to the Matrix. In that case, go ask Neo.
Pretty much only hydrogen and helium can work up sufficient velocities to escape. It seems no one knows the total amount that escapes. Considering how little hydrogen is on the surface of the earth, however, I'd say that it's roughly equal to the amount of hydrogen gas that is produced. So... maybe 100 tons per day? We're unlikely to run out anytime soon since the earth is, what, 4.5 billion years old and we still have plenty? Also, it's the most abundant element out there so we'll be able to harvest more if we need it methinks. Sorry this isn't an amusing answer. Couldn't think of anything even mildly funny to write here. It is an interesting question though :)