They require a large amount of force and feel similar to the Topre 55g.
I do not have access to American coins but I had a stack weighing 78g and it was enough to squash down the switch - remove one coin (weighing 3 grams) and it's not enough.
I had to remove the keycap to balance the coins and the keycaps weighs 3 grams (Left ALT) so my guess is between 73g and 77g.
Video of me mashing on it [sorry for quality]: