In 2018, the share of tertiary-educated adults reached 39 % on average across OECD countries …

„In 2018, the share of tertiary-educated adults reached 39 % on average across OECD countries, up from 29 % in 2008.“
OECD (Hrsg.), Education Indicators in Focus 77 (Jänner 2021), S. 2.