I buy hardware for new staff in Copenhagen, and none of the Danish people ask for the US or UK layout.
People from other countries are more likely to ask for an English layout, generally UK if they're from Europe (it keeps the ISO enter key shape) or US otherwise.
Wouldn't say it's that rate, but I'm pretty sure less than 10% of German programmers use US intl, maybe 5%?
I switched like 10 years ago and it's really a lot better, even if I have to customize it a bit to be able to type äöüß (via caps+aous).
But I'm peculiar anyway as only my Linux/work machines have that, I still use a German qwertz on Windows on my gaming machine so I generally switch layouts once per day, which only works with different physical keyboards so it feels different ;)
Bear in mind I'm in Denmark, I'm sure Germans-in-Germany are different.
Danish keyboards are obviously the default here, but it's usually not much hassle to get UK/US keyboards for laptops. Buying a laptop with a German keyboard is more complicated.