I remember when I first started attending meetings. They had a congregation split 4 ways, and we averaged more than 100 people for the public naptalk. This was in the late 1980s. Attendance below 100 was rare for these napsdiscourses. The weekday meetings were thinner, but they used to average in the high 80s and higher.
Then, about the mid 1990s, I began to notice a change. I think about 1991 or 1992, it became quite normal for the Sunday meetings to have well under 100 in attendance for a congregation of about 85 publishers. The Theocraptic Misery School (?) averaged sometimes less than 60 in attendance, and I have seen the second school cancelled because there wasn't enough people to support it. There would be a great big cavity in the front as people sat near the rear. This pattern was static, as there were attendance figures averaging in the high 50s and lower 60s for most meetings.
The bad news is that field service attendance has been stable. When I went out, I hoped no one else would show up and I could go back home. I did not notice any trends toward this, but I did notice a spike during the summer months and late in the month for no-shows. There would always be this auxiliary pioneer with a van sitting there, with the van still running, when I got there (usually about 15 minutes early). Most weekday mornings, there would be an average of 7 or 8 people out. This was stable through the 1990s.
More bad news. Starting about 1999, our congregation experienced regrowth. The numbers would climb back toward 110 for Sunday (when I did attend, I could see the attendance slips posted on the bulletin announcement board. They also had about 15 average for our book study (there were 5). The other congregation sharing the Hell saw some decline in membership: In the late 1980s, they had an average of 130 on Sunday; by 2002, it was down to 60.
I think my ex-congregation has a problem with poor education levels. The lead hounder and his typical JW family are all adamant for the Tower--which is probably why visiting them was so boring in hindsight (and I would rather go to the dentist than go back there). They all act as if nothing outside the Tower meant anything. No wonder education is being banned again! Those with better educations are leaving, and the poorly educated are replacing them. I doubt that anyone of those has Internet, or if they do, it is for spamming people that have been missing a few meetings.