The trend in NZ in more recent census reports is about 20 percent more are endorsed as affiliated with the JWs than those counted as publishers - because it asks about affiliation not active participation. In addition, each child has that question (which parents answer). And, of course, those who are "inactive" but still believe JW organization is the "Truth" can also endorse affiliation.
On another thread, I included a breakdown from the Aust census of JW affiliation vs age, in 5 year cohorts. If you subtract those in the 0 to 5, 5 to 10 and 10 to 15 cohorts, you get roughly the number of those who identified with the borg is roughly the same number as the publishers. As 10 to 15 year olds seem generally to be publishers, my guess would be that the number of people who believe but don't publish would be closer to 5%. That being said, I can't understand how they manage to get the numbers to the memorial attendance.
...and for the first time in decades, the number affiliated with 7th-Day Adventists was greater than the number affiliated with JWs...
Same in Australia in 2011 census; SDA overtook JW. From memory, Mormons have overtaken JW's in Aust, as well.