As far as I know, the best source for this type of breakdown is:
Avery, Christopher, Fairbanks, Andrew, Zeckhauser, Richard. The Early Admissions Game: Joining the Elite
Here is a source of a summary report of the book: ksgnotes1.harvard.edu/research/wpaper.nsf/ rwp/RWP01-049/$File/rwp01_049_avery_rev1.pdf
Another discussion can be found at
http://www.ericdigests.org/2003-4/early-decision.html
From your post, I do however, have to assume that you will not agree with the conclusions of the reports.
PS There was a discussion about ED on the parent's forum:
Where is the chart showing ED advantage over RD? Anyone?. While it does not address the breakdown of ED and RD pool, it is hard to overlook the advantages of applying ED. Just take a look at these two LAC schools:
Wellesley
Fresh(wo)men 591
Applicants 3912
Admitted 1476
Admit rate 41%
ED Apps 180
ED admit 123
ED Admit Rate ............... 68%
Smith
Fresh(wo)men 696
Apps 2993
Admits 1694
Rate 57%
ED Apps 192
ED Admit 156
ED Admit rate .................81%