15.6322%
Depends on what you want. How many colours do you want to have? How do you want the colours to transition? Do you want any shadow effects? Do you want to animate the lifebar? In my case, at least three (red, purple, blue), gradual transitions with possible bigger chuncks around the two most important points (20% and 50%), darken the middle part so the upper and lower edge stand out and no animation. Decisions, decisions. I'm happy I want to use transparent markers.
