Interesting. In the summary, it's not clear what qualifies as "compulsory health insurance":

> Health care is financed through a mix of financing arrangements including government spending and compulsory health insurance (“Government/compulsory”)

Digging into the source report[0], we see the following footnote exclusive to the US:

> All spending by private health insurance companies reported under compulsory health insurance. Category “Other” refers to financing by NGOs, employers, non-resident schemes and unknown schemes.

[0]: https://www.oecd-ilibrary.org/sites/ae3016b9-en/1/3/7/4/inde...