Any discussion of the WTS' numbers and the "growth" these numbers suggest has to take into account the inconsistency built in to their counting methods.
Counting time in field service is totally arbitrary. You won't find a memo anywhere that specificies exactly how such time is to be determined; it's left up to the individual. The method of counting time is determined by all sorts of whims. One person's 45 minutes is another's 3 hours. Traveling overseers know this, thus the WTS knows it. Yet they present the number of hours in the annual report as a precise figure and hail the fact that "over one billion hours" were spent in the field ministry last year. The number of magazines placed, return visits made, etc., are often made up on the spot by publishers responding to an urgent phone call asking them for numbers for a report for which the deadline has come and gone. These numbers, too, are categorized and published as factual.
Counting attendance at assemblies is also arbitrary. Some brothers attempt to count individuals in seats while others determine the total number of seats that exist and subtract the empty ones to get attendance. Some attendees who are out walking around or in the rest room don't get counted, but estimates are often added back in to account for these. Also, those counting will often count everyone, including babies and small children; the number in attendance is obviously far higher than the number of attendees who are baptized. Even "visitors" are counted in the total. This is especially true at the Memorial, where those taking the count are acutely aware of how important it is to maximize these numbers for the annual tally -- which is then presented as a precise number.
In summary, everywhere a count is taken, it's clear that the numbers are "cooked." So why should anyone believe ANY of these numbers, including those in the annual report related to "peak publishers" or "average publishers" and percentage of growth?
This is the very Society that in one of its study publications makes the point that if someone has lied to you often, you naturally wouldn't believe anything else they tell you, whereas is someone has always been completely honest with you, there is a high likelihood they are always telling the truth.
Does anyone really expect the WTS to publish a report that shows they're losing as many people as are coming in and that the numbers are down (again)? Won't happen. These numbers are about as accurate as the circulation figures for "free" newspapers that are thrown on the driveway or left in open racks in grocery stores. The actual circulation of those periodicals? It's whatever the publishers say it is.