DoC's note led me to crunch some quick numbers for the last 2 decades. Interesting.
This is using Yearbook figures:
1989 Peak Pubs - 3,787,188
# Baptized 1990-1999 - 3,234,811
So, 1999 Peak Pubs should be 7,021,999.
1999 Peak Pubs - 5,912,492
A difference of 1,109,507 - or 34.29% of the number baptized.
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1999 Peak Pubs - again 5,912,492
# Baptized 2000-2009 - 2,699,241 (note this is 535,570 less than the previous decade)
So 2009 Peak pubs should be 8,611,733
2009 Peak Pubs - 7,313,173
A difference of 1,298,560 - or 48.10% of the number baptized.
So in the aughts, WTBTS lost amost half of what they gained in membership.
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2-decade figures
1989 Peak Pubs - 3,787,188
# Baptized 1990 - 2009 - 5,934,052
2009 Peak pubs should be 9,721,240
2009 Peak Pubs - 7,313,173
A difference of 2,408,067 - 40.58% of the number baptized.
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How much of the loss is due to older ones dying off and how much due to people leaving, I can't be sure. I'll leave more detailed analysis of these numbers to others.