"It's the safest single engined aircraft in the world" That's a bit subjective, I would say. Even if the claim were "safest single engined helicopter", you would still need to set its record against the likes of the Alouette III and Lama types which were chosen for Alpine rescue work and by various armed forces for very good reasons. In the years when I flew small single-engined helicopters (60's and 70s) I never heard or read of one Artouste 3 engine that failed except that it was starved of fuel. Nor were there any blade and rotor control issues in that period, to my knowledge.
Someone has already mentioned the Jetranger tension/torsion strap issue.
I also have a very few Jetranger hours in my logbook and envy those who have thousands. Yes it is a truly fantastic helicopter, near-perfect in most aspects, but not the safest in the world. No, I'm not going to respond to the inevitable "fireworks" on the the subject of how the FAA/NTSB requires accidents to be recorded versus how it is done in the UK/EASA land. I won't even make the usual comment about "statistics" either.
When the notion of "safest single engined aircraft in the world" is raised, then it is sensible to include such venerable fixed-wings as the Antonov AN2 and the DHC Beaver.
Just my usual 10 cents worth, in the hope of stirring the hornet's nest.