Hi sbf, I don't have enough confidence in the data to read anything into that tiny acceleration in the median age. The main point is that it increased significantly. The higher it goes, the faster the future decline, and the harder it is to turn it around.
Just for interest sake, I projected the figures forward to see what they might be in 5 years time and 10 years time. All things being equal, i calculated that in 5 years the median age would be 48 and overall decline would be 4%. In 10 years, the median age would be 53 and there would be a further 4% decline. Of course, a lot can change and I wouldn't want to be held to those numbers.
Already, there are as many JW's over 75 as there are under 10. Probably in about 7 years there will be more JW's over 80 as under 10. I just wonder how teenagers in particular will cope with that, will young people generally be able to take any of it seriously, etc.
Of course, what is happening in Australia is probably happening (or has happened or will soon happen) in all first world countries.