aion skill level's how does it work?

ingame next to the IV or V or II (whatever rank of skill) there is a lvl where some skills say lvl 9 or 1 or 6 does this raise by how much you use the skill?

 

Skill levels pretty much work on two tiers, like Smite I level 1, I gain 9 levels and it's smite 1 level 9. I then unlock smite II which starts at level 1. The skills ability increases as you level, until you unlock the next tier level for that skill.. of course, some skills don't level, and some you'll never have more than I of.