Hell, I look at the delta between what my firm bills me out for and what I take home, and it's about 12% of my fully loaded day rate.
So 3200 becomes $4800 (or just under $57k a year) - that's still a good deal given what you'd get.
I've worked with eastern and central European developers and some of them are phenomenal (the skill breakdown is about equivalent to UK devs as a pool maybe tending towards them been slightly better but there will be some element of selection bias in that, language barrier is the biggest hurdle, many of them speak/write good English - my partner is Hungarian and her written English is at least as good as mine) but when the tiniest miss-understanding on requirements is costly during development and potentially devastating in production that really starts to matter.
20 USD / hour * 8 h/day * 21 days/month * 12 months = ~ 40,000 USD / year.
Of course, experienced ones don't receive that might higher salary either. About 5 years of experience would probably get you around double to triple the starting salary.