I have no idea what the stats are, but I am not sure why you assume those numbers.
The way I understand it, is that a MO person who goes off the derech may be more likely to maintain some Jewish roots. A yeshivish or chassidish person who goes OTD usually chucks it all. Anecdotal of course.
In a year above me in another school, I know of 1 person who married a non Jew.