Dunno where you are getting your figures from but I am getting them from the actual USAF. USAF itself says it has 450 hercs, they grounded a 1/3 of the fleet last year (123) when a cracking problem was found in the J's
Air Mobility Command head Gen. Maryanna Miller ordered 123 of the 450 Total Force C-130 Hercules aircraft to undergo inspection after cracking was found on the lower center wing joint, also known as the "rainbow fitting," of one of the planes. The Air Force observed that the crack could lead to the dismantling of the wing from the aircraft, leading to the partial removal of C-130H and C-130J aircraft from the sky.