No one has yet offered any coherent explanation as to why Rabbi Pruzansky, a modern orthodox rabbi with much direct experience (and commentary) in what is going on in the modern orthodox world, would publish statistics that would make modern orthodoxy look really bad, if it isn’t rooted in fact.
My take is that whatever the merits of the precise percentages, the overall point is that the statistics are really really bad. Rabbi Pruzansky may have mentioned the study, but he in fact speaks from first-hand pulpit experience in that community.