My dad goes to a small town congregation in the "bible belt" country south United States. I haven't been there in years, but when I did visit him there long ago in a different life, they had like 30-35 people for Sunday meetings, and all but 2 couples were over the age of 50. Zero children. All these years later I can't imagine them as having done much to increase membership. I'd bet quite a few of the elderly are dead and gone now too.
This same situation probably exists all over the US and perhaps even moreso in far more secular countries in Europe. Yes, they still are growing their numbers (albeit at a lesser rate than they used to, plus losing lots of members), but this can most probably be credited to growth in developing countries that are religious and perhaps not as advanced as more secular nations.
I hope that I live to see the day that the JW's go kah-put!