I sure do, in fact I've emptied more helium tanks in my career than 99.99% of the population I'm certain (10 years in gas chromatography). I know that it's more profitable to sell 99% pure helium as "party use" than it is to sell the quality of helium I use, the difference is I use enough of it that there's still some profit there, (the same reason the US of A sold off the "extra reserves") and as long as it's an unlimited resource (short term it certainly seems to be from the capitalist mindset) they're going to milk every cent of profit out of it as quickly as possible, so they'll still make some and sell it to me.