Nathan,
I think your question is in jest, but just to clarify to lurkers, what I meant was the median age of JW's in Aust went up in 2011 compared to 2006, and also compared to the median age of the overall population. They are not individually getting older at a faster rate. There are just fewer young JW's coming through the life cycle.
I don't have the data with me at the moment, as I have it on another computer. I will pull it out and post it, but it might take me a day or so. One of the things I created was a breakdown of no of JW's per 5 year age group from 2006 and 2011, and given the censuses were 5 years apart, I could line the 2 data-sets alongside each other and see how many dropped out of each 5 year cohort. (The results were unsurprising, but interesting all the same.)