Personally, I read it more as "95% of it is over a single medium", and that it's less about the actual length.

But, for the sake of comparison, the US has 6,853,024km of roads and 95,932km of expressways according to Wikipedia [0] (far and away the most of any country in the world, interestingly). Broadband penetration for the US is >50% for any demographic [1], so extrapolating there's millions of kilometers of internet cable just to support the US's internet needs. So maybe that number is pretty amazing after all...

[0] https://en.wikipedia.org/wiki/List_of_countries_by_road_netw...

[1] https://www.statista.com/statistics/710877/adult-home-broadb...