Somehow it's really hard to find numbers, but AFAIK at least Telekom and 1&1 don't use CGNAT for home connections, which already rules out that 77% have it.
German ISPs commonly seem to have an option of their "old" platform (v4 only, no v6) or their "new" one (v6 and CGNATed v4). Maybe you're on their old one? Or maybe they only use it for certain account tiers or somesuch.
