Nicholas Moreau wrote:
http://en.wikipedia.org/wiki/Category:Redirects_from_titles_without_diacriti...
I think this category is actually a list of redirect, from the diacritic-less spellings to the diacriticed actual articles. There's over 309 K redirects. Not sure though.
An interesting category, but seems occasionally misused (for example, in (ISC)2 somebody confused superscript with a diacritic). This category, however, indeed shows redirects from articles without a diacritic to those with a diacritic ("The pages in this category are redirects to articles whose titles have diacritical marks.") Thanks for the find!
The one that shows redirects for titles with a diacritic to one without a diacritic would be http://en.wikipedia.org/wiki/Category:Redirects_from_titles_with_diacritics ("Category:Redirects from titles with diacritics") This one has about 6,5k articles.
Thanks for the categories, as imperfect as they are they are nonetheless quite useful to know about, and clearly show that Wikipedia does use diacritics much more often than not.