[nabla9]

Effective marginal tax rate, not marginal tax rate. EMTR is what how much you actually get when taxes and reduction of welfare with increasing income is taken into account.

>Do you have a source for that?

Yes. https://vatt.fi/documents/2956369/3012213/muistio_50.pdf

It's in Finnish, but if you go to page 13 there is a nice graph. x-axis is wage, EUR/month, y-axis is effective marginal income tax in year 2015 for single person household who pays rent 440 EUR/month. Effective marginal tax rate is the red dotted line.

In page 20 you can see even what single adult with a child can have. I was actually wrong, the effective marginal tax rate can spike above 11% in some cases.