The OECD reports numbers that include public expenditures. I'm not sure where I'd even look to find the precise methodology, but at some point you have to trust that the experts know what they're doing and are reasonably impartial. And sure, Sweden's overall tax rate is probably a lot higher, but they are providing a lot more services than the US government with that money beyond just healthcare. So the choice probably isn't between ~30% tax rate with private healthcare[2] and ~60% tax rate with public healthcare; even if the full ~$10,000 health care expenditures per capita were spent on taxes instead, that's only about a 17 percentage point increase on the per capita income of $60k.
[1] https://en.wikipedia.org/wiki/List_of_countries_by_total_hea...
[2] http://thehill.com/policy/finance/238735-average-us-worker-p...