* VodafoneZiggo has 40-45% of the home market, but also 25-30% of the business market and 20-25% of the mobile market [1]. They seem to offer IPv6 on their home and business connections, but not on their mobile connections [2, 3, 4].
* KPN (35-40% home/biz, 25-30% mobile): IPv6 for homes (except older modem types) and mobiles, but not by default for businesses [5, 6].
* Odido [ex T-Mobile] (30-35% mobile, 5-10% home/biz): no IPv6 across the board [7, 8].
Their data must just be out of date. It's been over a year that I've had IPv6 with Ziggo business and home. As you say, Vodafone mobile still only does IPv4 though.
The Ziggo shift would have made a huge impact on the national total.
* VodafoneZiggo has 40-45% of the home market, but also 25-30% of the business market and 20-25% of the mobile market [1]. They seem to offer IPv6 on their home and business connections, but not on their mobile connections [2, 3, 4].
* KPN (35-40% home/biz, 25-30% mobile): IPv6 for homes (except older modem types) and mobiles, but not by default for businesses [5, 6].
* Odido [ex T-Mobile] (30-35% mobile, 5-10% home/biz): no IPv6 across the board [7, 8].
* Eurofiber (20-25% biz): has IPv6 [9].
* Delta (5-10% home): no IPv6 [10].
* Unspecified smaller ISPs (0-5% home/biz, 10-15% mobile): unknown.
* Finally, a number of wholesale access providers, where the customer presumably has a say in IPv6 support.
This works out to 75-90% IPv6 in homes, 45-60% in businesses (ignoring wholesale) and only 35-45% for mobiles.
So, the mystery is not solved, because this data still doesn’t support Google’s 13% figure…
[1] https://public.tableau.com/app/profile/autoriteit.consument....
[2] https://www.ziggo.nl/klantenservice/internet-wifi/ipv6-bij-z...
[3] https://community.ziggo.nl/t5/Internet/Instellen-ipv6-zakeli...
[4] https://community.vodafone.nl/t5/Archief/IPv6-op-mobiel/td-p...
[5] https://www.kpn.com/service/internet/ipv6.htm
[6] https://zakelijkforum.kpn.com/internet-bellen-9/ipv6-werkt-n...
[7] https://community.odido.nl/bekabeld-internet-492/ipv6-wannee...
[8] https://community.odido.nl/netwerk-en-verbinding-559/wanneer...
[9] https://www.eurofiber.com/nl-nl/snel-internet
[10] https://www.delta.nl/klantenservice/vrije-modemkeuze/, expand ‘stap 4’