How Many Common, Unique Letters Do *You* Think There Are?

[oshfdk]

1. I know you don't know. I don't know. None of us know. But if you had to put down one number, not a range, what would it be?
   

If I absolutely had to put one number, the number would be ~12 (10-14), if "common" means occurring in almost any long paragraph. Generally, I think EVA does a very good job separating meaningful differences from minor variations.