When you apportion something such as blame, you decide how much of it different people deserve or should be given. The experts are even-handed in apportioning blame among EU governments. to decide how something should be shared between various people (apportionner, from portionner )
Specifically, to do so in a fair and equitable manner; to allocate proportionally
To divide and assign in just proportion; to divide and distribute proportionally; to portion out; to allot; as, to apportion undivided rights; to apportion time among various employments