> Disclosed leaks (massive as they are here) are still 10%
A very good question! Might be less than 10%, actually, wouldn't you think? If you know Mr. Troy, drop him a message; I'd like to know his opinion, as I haven't seen academic papers estimating these things.
Then, a further question is that as data keeps and keeps accumulating, bigger and bigger and bigger and faster and faster and faster, more and more and more will leak in the future, including more and more sensitive (read: non-personal) data.
EDIT: less, not more, sorry for the inconvenience.