So, fly a hundred single engine helicopters over congested areas for a thousand hours and give them all engine failures - how many will make a 'safe' forced landing and how many will result in fatal accidents?
Now do the same with twin engine helicopters and give them a single engine failure - what about those results???
Any clues there as to why some authorities might choose to limit singles over cities.
TR and gearbox failure will bring them all down so don't try and skew the stats with those.