An
Age Profile of License Holders is available on the CAA website.
According to these statistics (as at 1 April 2004), the oldest ATPL(H) was 75, CPL(H) was 67, and PPL(H) was 81.
I can't comment on what sort of percentage of the population would be able to fly helicopters, but I calculated that approx. 0.008% of the UK population are helicopter license holders with current medical (based on the statistics above).
