To try and compare UK knife crime with American Gun Crime is so stupid, I presume you were joshing.
On Average the UK, which has a population about 70 million has about 70 gun deaths each year (Give or take)
If you compare the rate per 100,000 people between the UK and America you will find that America has so many gun deaths nobody has any time to count them any more.
A gun has ONLY one (Primary) Purpose, that is to kill. Shooting where you are not trying to kill anyone or anything appears to be rare, based on the number of recorded deaths.
Why Americans have this fanatical LOVE for all things gun related, I do not know. Oh yes, it's your god awful 2nd Amendment, Might have been relevant in the beginning but Hands up anyone that thinks its a good idea to have millions of people carrying around loaded firearms when they can barley hold the gun strait and have bugger all training on when NOT to use a gun. Even you cops seemed to have almost NO training on the proper use (and avoidance) for guns. Most of them seem to feel it justified to automatically pull out their guns and start shooting. I gather that in America most cops have a few weeks or months of training. In the UK it is 2 years, and that is WITHOUT any firearm training. To be able to use firearms in the UK means the police have to have much more extensive training