Honest way to show your skills in Portfolio

So i have started seeing this a lot in portfolios of designers.

This person has a title that says "My Skills", and at the bottom are bar graphs that are in percentages. So I asked this question - "What do the Percentages mean" ? If you say Photoshop = 85%, does that mean you know 85% of all there is to know about Photoshop?

What is a good way to represent this