The confusion (intentional or not) may stem from that 90% figure being of all ICU patients, covid or not, or just as a proportion of covid patients. People are still getting into car accidents, shot, and having heart attacks.

As a datapoint, my county publishes daily hospitalizations by vaccination status. Some vaccinated people are showing up, maybe 15-20%. So less than 90% unvaccinated there. But that is just hospitalization. For more serious outcomes I'd guess the unvaccinated percentage is higher even than 90%.

This is meaningless without knowing how the base rate (what portion of people in your country are vaccinated) compares to the US. If more people are vaccinated and vaccination is anything less than 100% effective against hospitalization, then by definition a smaller portion of those hospitalized will be unvaccinated.