Not really relevant. The majority of teens isn't able to make an informed decision about which is better anyway, and in fact none of the 2 is recommended anyway unless you count in AOSP-based distributions (based off of the open source Android without Google apps), then Android wins of course. But when you compare iOS vs. proprietary Android, it's like comparing 2 different forms of diseases.
So yeah while statistics are interesting it's important not to interpret too much into some. Like, "majority of teens dislikes Jazz music". Well, it doesn't really matter whether they dislike it or not. Popularity doesn't represent quality necessarily. Sometimes, but certainly not always.
In Germany the mobile landscape is more "diverse", I'd say closer to 40%/60% iOS/Android from my own observations. And since we "care" "more" about privacy in schools or public institutions (we still care plenty little but I guess Germany is on average at least known for being a country that does more for data protection than others, so maybe that counts as something?), it's also probably less iOS infested, although I do know that some schools and public institutions do use iOS devices. But I don't think everyone does.