Some more data points, not seeing a significant difference:
5 mins ADS, standing = 3 points
5 mins ADS, crouching = 3 points
5 mins running into a wall = 7 points (roughly exact, my autoclicker is a plant pot...)
5 mins crouched running into a wall = 6 points (7 at 5:20)
5 min swinging a bat = 15 points (pretty exact)
5 min swinging a bat crouched = 16 points
Basically unskilled character, some skills will modify the consumption; but none should increase passive, crouched. But I don't know what the book for "no stamina use while crouch sprinting" actually does - it Might just increase stamina regen while crouched, and increase the recovery costs even passively. And can't say I remember all of the effects...