Yep it's 5%
And may I add that skill level doesn't really matter as much as some people may think
Thing is a lot of people playing these types of game are completionnists / perfectionnists, and want their skill levels as high as possible
But I recently discovered that the game not being finished, the progression curve of the game isn't either. i.e you don't need to have 80 across the board to have an end-game character. In my current playthrough I kind of gave up on the bow early, and started using it more when reaching the mountains. Having 28 bow skill got me to the plains with no problem. And I've died a good dozen of times in that playthrough ; the current difficulty setting doesn't require you not to die. You can die safely and still have your character ready for you're current progression