The source on the "10x less risky than going down a flight of stairs" is https://static.guim.co.uk/sys-images/Guardian/Pix/pictures/2.... That shows that in the UK in 2010, 655 people died from falling down stairs. That translates to a 1 in 100,000 annualized risk from falling down stairs -- the relevant comparison is "10x less risky than using stairs a typical amount for an entire year".

Interestingly, running the numbers for the UK shows that the annualized per-capita risk of dying on stairs in the UK is more than twice as high as it is in the US.

Thanks. I'm going to take that one out. Makes it simpler not to do annual risk. Risk difference UK/US is odd! We thought you guys had it bad with gun crime, and didn't think about the stairs....

To be fair also probably all of these get more likely as age increases. I bet very few 30 year olds dies of falling down the stairs...