This is mobile phones dominating that number. Almost every 4G / 5G phone right now uses a dual stack IPv4/6 connection. This is not necessarily problematic but home broadband is still lagging by a lot. I sometimes never get a prefix assigned. I have to redial PPPoE as IPv6 link uses IPv4 session. It's not plug and play for home broadband unless you use their modem router combo which has other issues.