The only real growth in numbers comes from born ins.
Really, honestly, how often do we learn of a person coming in as a result of the witnessing work?? Very rarely....and those that do are generally 'disfunctional' members of the community, not average well adjusted people. Perhaps people in "need" of a sense of belonging, or some emotional reason.
So that's why the organisation encourages children to be born now, and nurtures such ones with the propaganda videos....