One death in the UK every week and a half seems highly probable to me, indeed, to be brutally honest - the figure (if correct) seems rather on the low side? (As a JP, I often saw the effects showing through the following day.)
How many were injured in fights and were arrested for affray and similar?
How many choked on their own vomit?
How many were glue sniffers?
How many died of alcohol poisoning?
How many were drug overdoses?
How many died of natural causes?
How many suicides?
In the UK - every death in custody is investigated to the nth degree.