Your incorrect.
Please provide a URL of documentation.
...
P.S. Sorry 'bout that - previous post should read "...can only provide ancedotes..."
It is from a paper by Kristin Transgrud of UNC, Chapel Hill. She also presents a table showing the size of the populations affected.
Note that a number of the savages who killed our people on the 11th of September came from shaded regions (Atta was from Egypt, for instance).
Whether or not this vile practice is sanctioned by Islam or merely associated with it is not relevant. The more widely known it is, the better!