Where are the most left handed people?

i am left handed and so is my brother and dad and most of my cousins, so i know it is hereditary, and my family also has alot of twins and i've heard that there is a conection with twins and lefties. i've heard of places where the is an unusually high rate of twins, so there must be places with alot of lefties. does anyone know of a country, ethnic group, occupation, or even city or religion that has more left handed people than the others??