What percentage of people are lefty?

13% of people are left-handed, up from 11% a few decades ago. The story that right-handed people live, on average, nine years longer than left-handed people is a myth.
The word for left in French means gauche and in Latin it means sinister. The Latin word for right is dexter, from which came "dexterous". Ambidextrous means literally "both right."
In medieval times, left-handed people could not become knights because it was thought that they were descendants of the devil, it is said. Spiral staircases in castles ran clockwise to allow knights all right-handed to battle intruders effectively.