I don't know which dataset you're using for the Netherlands, but it's way off: https://www.surnamemap.eu/netherlands/index.php?sur=van+der+Zwan&s=Search https:

I don't know which dataset you're using for the Netherlands, but it's way off: https://www.surnamemap.eu/netherlands/index.php?sur=van+der+Zwan&s=Search https://www.surnamemap.eu/netherlands/index.php?sur=van+der+... https://www.cbgfamilienamen.nl/nfb/detail_naam.php?gba_lcnaam=van%20der%20zwan&gba_naam=van%20der%20Zwan&nfd_naam=Zwan,%20van%20der&operator=eq&taal= https://www.cbgfamilienamen.nl/nfb/detail_naam.php?gba_lcnaa... EDIT: actually, it works if I use "vd Zwan", which is fine by itself, but that contradicts the instructions on top of the page: https://www.surnamemap.eu/netherlands/nl/index.php?sur=vd+zwan&s=Zoeken https://www.surnamemap.eu/netherlands/nl/index.php?sur=vd+zw...