Good questions, George -- you note that I covered the last issue in my original post. I am interested in active musicians, so singers would count in my books if they belonged to a choir, a choral group, or as part of a band, or sang regularly with their families or friends in a really engaged fashion. This begs all kinds of questions: if you took into account everyone who went to church and sang a hymn every week, then the numbers would go way up. If you added people who do karaoke, they would probably go up again. I am trying to identify people for whom some kind of skill or constant endeavour (however informal it might be) is engaged.

But anyone can add to this any way they like. I was just cutting it that way to suit my fancy. It is hard to find any numbers of any kind!!

yours, Peter T.