On another thread, by sbf titled " New study - JWs by far the least educated religious group in Canada, Australia and New Zealand", I added a table created from Australian census data, relating to young ones leaving. Here is a repeat:
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To explain, what I did was take 5 year cohorts from each census and lines them up so that you can see in each age group, how many remained JW's over a 5 year period. Eg, there were 5119 JW's between the age of 15 and 19 in 2006, but in 2011 that same group (now aged between 20 and 24) dropped to 4597. The fourth column is just the difference between columns 2 and 3, for ease of reference.
One of the questions in the 2011 census was in relation to which state or territory you were living in in 2006. Using the answer, you can tell which ones were living overseas, shown in the fifth column. The sixth column is just the 4th col, less the 5th col, for ease of reference.
This data shows the kids leaving in droves from 15 to 24. However, it also shows a trickle back in subsequent years, and those re-attending taking young kids in with them. It didn't occur to me until after I prepared this chart, but my wife is a classic anecdotal example of this drift back. I know another ultra-dub who was born in, was completely out and df'ed as a young adult, and rejoined decades later.
So, unfortunately, if history is a guide, some of the 30 children that pale emperor knew will probably drift back into the borg, over time.