Anglican affiliation has declined 17 percent ”“ from 554,925 to 459,771 ”“ over the past seven years, according the latest census.
Partly this is because the average age of Anglicans is very high.
Last census there were 41,000 Anglicans over the age of 80, only slightly less than those under 10. But this still means that many Anglicans in 2006 have changed their affiliation since then ”“ probably to “none”.
Read it all and there is much more there on New Zealand as a whole.