Funny but no matter where I look, I can’t find a figure for how many people come of age/graduate/finish apprenticeship/get licensed or in some other way enter the workforce in a given month, or for how many people retire/quit/die or in some other way leave the workforce.

Without knowing what those numbers are, this number is meaningless - there’s no way of telling if it outstrips, keeps pace with or even lags behind the likely ongoing growth in the labor pool.