_Morpheus: Another factor in this would be the staff held for construction in warwick.
Yes, and it admittedly gets a bit hazy regarding who the WT are counting - but the overall trend over the last 55-or-so-years seems very clear when viewing the ratios.
This is what I commented about in an earlier post in this same thread:
I understand that Bethel is VERY hierarchical and specific with reference to what you are - ie are you an 'actual' member of the Bethel Family. I understood from those that have worked full-time on construction projects alongside working Bethels, including international, they had to be 'careful' - although the congregation they were assigned to viewed them as Bethel Family, they were not! they were construction.
Also note the language used below
Awake 22 December 2000, page 19
Truly, it is remarkable that the number of branch offices has increased from one a hundred years ago to 109 today that serve the needs of Jehovah’s Witnesses in 234 lands. And to think that these are staffed by some 13,000 dedicated Christian volunteers! Surely, their work along with that of the some 5,500 volunteers associated with the Society’s headquarters has been vital to the fulfillment of the prophecy of Jesus Christ that ‘this good news of God’s Kingdom would be preached in all the inhabited earth before the end comes.’—Matthew 24:14.I haven't included the 13,000 in my table (as it is not precise) but it fits for the number of Bethelites [added: as per late 1990s on above chart] - notice WT makes a clear distinction with 'volunteers associated with the Society's headquarters' - they're not 'Family'.