This is handy to know - I completed the tax documentation as a 'non-US person', so don't pay the withholding tax, but had wondered what it might be, as it could potentially be less than I would pay here in Spain, and be worth switching. 30% wouldn't make it worthwhile.

Plus this also raises the issue of which government gets to use that revenue. I'd rather pay a little more here, where I have a tiny degree of influence over fiscal decisions, than in the US, which is about to descend into another of its frequent periods of misrule.