Are Catholic schools run by seculars a post-Vatican II novelty?

[Geremia]

• Jamie Faser Arthur, "What Is the Lived Experience of Laywomen Who Serve as Catholic Elementary School Principals in Their Roles as Faith Leaders?" (Georgia State University, 2012), 11:

In 1965 indicate there were 13,292 schools serving 5.6 million students with religious orders positioned in nearly 100% of administrative positions and 58% religious as full-time professional staff (Guerra, 1991). However, 2009-2010 figures show a sharp decline with only 7,248 Catholic schools, 2.2 million students, and only 3% religious orders serving as full-time professional staff (NCEA, 2010). [...] the closing of nearly 50% of its schools and 97% fewer religious serving the remaining ones

^{(my emphases)}

[Mysterium Fidei]

Aren't most Novus Ordo nuns over 80 years of age? The destruction of religious orders and Catholic education is just another consequence of the Vatican II Revolution.

[Geremia]

Aren't most Novus Ordo nuns over 80 years of age?

The ones who left religious life or the ones who stayed in it? Didn't the vast majority leave religious life (cf. Rebel Hearts)?