Actually, per-student private non-profit school borrowing was the highest, since per-student private for-profit school borrowing had fallen (see table 1 and figure 1 in the linked report). However, private for-profit schools had the highest percentage of students borrowing. The private for-profit schools generally had the students with the lowest EFC, according to figure 2. Other demographic comparisons are shown in Table 2.
Of course, the educational value gotten at many private for-profit schools can be dubious.