The numbers switch was slow, though. My parents started school after the change was officially made in the 50's and would have learned the new forms in school, but still used the old form enough in the late 70's and 80's that I picked up a preference for it from them, and you still find people of my generation (I'm born in '75) using the old forms pretty often, if less now than when I was younger.

(If anyone here wonders if this is the same "Samnorsk" as in Vernor Vinge's "A Fire Upon the Deep": It is. For people who know Norwegian, Vinge's books have several Norwegian-inspired terms. E.g. "Nyjora" is "new earth".)