I imagine it's much higher, at least 5 nines, mostly because they tend to go straight from their rolls to containing garbage. They also don't blow away so easily.
However we probably should stop using them. Merely banning will just be met with confusion, since they're an integral part of the waste disposal system. But in my experience, and the experience of others in this thread, a good food waste + recycling system virtually eliminates all solid waste, and therefore the need for garbage bags. All solid waste, that is, apart from plastic packaging. Probably we should get rid of that too.
However we probably should stop using them. Merely banning will just be met with confusion, since they're an integral part of the waste disposal system. But in my experience, and the experience of others in this thread, a good food waste + recycling system virtually eliminates all solid waste, and therefore the need for garbage bags. All solid waste, that is, apart from plastic packaging. Probably we should get rid of that too.