Well apart from the two Indian guys in the photo the subjects all look pretty decrepit to me.
Recruiment in the West was at its peak from 1972 to 1976 and in the UK at least, there was an unusually strong bias (when compared to other new age movements) toward the under 21s with many 16 and seventeen year olds becoming premies. Taking the year 1976 as a terminus and a lower age of 16, I think it is probably reasonable to suggest that the majority of Rawat's long term Western followers were born before 1961. This would provide for a significant number currently aged 43 - 49.
I'm not clear how this would translate into a calculation for the number who are 50 plus although a 20/80 - 30/70 power relationship probably describes the under 50/over 50 ratio.
In the UK the '76 terminus was concurrent with the rise in punk and a rapid politicisation of young people. While the decline in recruitment undoubtedly had its roots in failures of Rawat and DLM, Rawat was never going to appeal to a generation whose key word was fuck and whose drug of choice was speed, in the way that he had appealed to the punk's older siblings who were seeking to revive peace, love and acid.
Nik