Kills 99.9% of germs

Usually, they say it kills 99% of all "known" germs so they cover themselves for the eventuality that other germs will be discovered. I would think that they can not really be sure if all germs are killed although it might be deliberate because it would be really bad to have absolutely no germs at all. We need some germs so we can fight them and keep our immune system working.

Apparently nothing will kill 100% of germs. They aren't allowed to say it will because that's against the trade descriptions act or something like that. Maybe it's just that 1% of germs have legs and run away.