This seems to be
- a random selection of countries rather than the top ranking ones and also
- the numbers seem to be pretty low compared to other sources.
At least as per Wikipedia, Mexico has around 19%, Brazil /China/Taiwan 14% etc. I live in Germany and here vegetarians are typically estimated at around 10% which corresponds to the number in Wikipedia but it's not even listed in the graphic above.
I don't know if these filters for permanent installation have some techology to prevent this, but the smaller jug-style water filters increase bacteria growth if you don't regularly exchange them. I think for a part with such a huge internal surface that is permanently wet, this is really hard to avoid unless it has a special desinfection mechanism.
https://www.businessinsider.com/water-filter-mistakes-increase-risk-bacterial-infection-2021-8
For short-term use while hiking I use water filters by Sawyer or Katadyn so far without problems. But I rinse them with chlorine and vinegar before I put them away for storage.