I think some countries are missing here.

I'd guess that they're using Eurostat data, but the UK is present, and they stopped participating in Eurostat when they left the EU. So either it's not that, or it's old data.

A bit off-topic, but I kind of wish that the UK and some of the other countries in Europe could participate in some level of voluntary, best-effort participating to share data. Like, okay, if you're not in the EU, you aren't bound to use the same statistical standards that EU members are, but I am pretty sure that some countries do or don't care, and it's kind of obnoxious that it makes it harder to compare datasets spanning all of Europe.