Auto-translated
in the third game, 3
3
3
in the fourth game, 5-5-5-5
5-5-5-5
in the fifth game, 3-1-1-1, and even then, they are just small bonuses.
In the third game, skills don't have any additional abilities or increase anything... but in the fourth and fifth games, they do! Tactics, for example, adds attack, and in the fifth game, dark magic gives the Lightning Lord its ability... and so on!