I don't know about how fast it'll go to 60%, but what's the 'progressive enhancement' about it? You still have to implement and debug the old list markers, and

I don't know about how fast it'll go to 60%, but what's the 'progressive enhancement' about it? You still have to implement and debug the old list markers, and you'd use the new elements to do just the same thing, so why bother until you can rip out the old code and replace it entirely?