This isn't really reporting a death rate, it's reporting the distribution of heights given you died falling from a height.
I'd guess falls from higher heights are more deadly, but less likely (you're more likely to use fall protection on a 8 story roof than a 1 story roof, I'd guess; and there's also a lot more 1 story roofs than 8 story roofs)
In other words, assuming falling probability doesn't vary with height, its estimating what % of time people spend at each height * probability of a fall being reported at that height * probability of death at a given height.
It probably depends a lot on what you are going to hit as you fall. A drop onto a safety line over an empty void may be safer than a 2m fall onto a piece of equipment.
I'd guess falls from higher heights are more deadly, but less likely (you're more likely to use fall protection on a 8 story roof than a 1 story roof, I'd guess; and there's also a lot more 1 story roofs than 8 story roofs)