commonsense,
if you add up all the 12th graders from all the by schools in north america (include toronto/montreal) you get no more than 2k-3k girls applying to e”y in total!. yes, many apply to multiple seminaries, but there are a lot of seminaries, figure approx 15 by type seminaries.
anyone applying to lahav or mezuraz, which are half year sems, are probably not applying to nachlas.
anyone applying to the sems that stress hashkafic growth OVER academic growth (all sems have both, everyone stresses something differently) i.e.: machon raaya, ateres, … are also not applying to nachlas.
anyone applying to less strict sems (darchei binah, peninim…) are not applying to nachlas