Its done on % of population, per 1000 it says, small or large area its population density!
.............and it still seems very high everywhere to me, I don't pretend to be an expert but the figures seem very high everywhere, could it be a typo, should it be per 100,000?
Even in Wiltshire, the LOWEST region, it would mean approx 1 in every 5 households would suffer from knife crime, I'm struggling to believe that!!