In football (at least in Europe), the second half of a football match almost always gets a longer additional time (seems to be 3 minutes on average) than the first half (seems to be 1 minute on average).
Why is that?
Generally teams make more substitutions in the second half, which means more stoppage time. Very rarely is a substitution made in the first half, while most teams use all 3 subs in the second half.