Betsy, Try posting to Julia S.  I think it was she who originally put up those studies.  Also, look on p. 2 of the controversies board.  Post by Sue, from the UK, now way down at the bottom of the page, from 12/2.  If you go to the link she posted, then look at the end of the article, in the bibliography, there are a couple of other studies listed there, as well, which seem to have the types of numbers/statistics that you are looking for.