The percentage decline seems significantly greater in the running sections, to me. And I suspect that the attrition rate among competitive runners is greater, because of their greater susceptibility to joint and connective tissue damage.

But I'm not here to argue about the merits of cycling vs running. The message is clear - if you keep healthy, and keep training, you can continue to perform at a surprisingly high level well into old age. In my own case I aim to go under the hour for 40k aged 60. I'm reinforced in my belief that I can do it by the knowledge that there are 80 year-olds in the UK who are faster than that. Inspirational, really.