Ratings range from 0% to 100%. The higher the rating, the better the gear.
Calculation
Rating is just a simple average of the votes on a piece of gear.
"So I was sitting in my cubicle today, and I realized, ever since I started working, every single day of my life has been worse than the day before it. So that means that every single day that you see me, that's on the worst day of my life."
--Peter Gibbons (Office Space)