Defined as a completely made up percentage of people that is in fact < 100%.
Good thing I left NL or I would have invalidated your statement! Actually, I don't know anyone who brushes twice daily.
Why don't you, isn't that a recommendation where you come from? I also don't know anyone who doesn't brush twice daily (I'm from Nordics).
Authorities making recommendations about minutiae does not really dictate much of the way I live my life. If they want to make it a law, fine, I'll brush my teeth in between the cups of coffee I serially drink from the moment I rise until roughly dinnertime when I then switch to alcohol (something strongly discommended by other authorities). My teeth are fine, 40 years and counting. Perhaps it's all a conspiracy by Big Toothpaste to sell more toothpaste.
I don't know anyone that doesn't brush twice daily. Am quite a sociable person and have lived in multiple European countries