“I think even charliehall once posted that at one time a high percentage of hesder boys went OTD (although now it’s better).”
I did post that. My source was a public statement by a Religious Zionist leader who had helped start the Army Preparatory Schools that dramatically reduced the OTD rate for RZ young people who did not want to go to a hesder yeshiva. Previously, the hesder yeshivot had dramatically reduced the OTD rate among their students.