Agree that there are significant numbers considering state alternatives and also significant numbers that don't. Impossible to say, out of the cohort applying for private, what are the precise numbers beyond saying that they are large.
My comment referred to the fact that the movement happening on or about state offer day could also be related to people holding multiple offers until close to the deadline ... in a world, like this year, where a number of schools have to be cautious with the offering because of over-offering last year (and might rely more on WL), I would not disregard the impact of this "extreme offer holding" and would very much encourage people to release their offers.