Sri Lanka has three main ethnic populations (Singhalese, Tamil and Moors) and they generally live harmoniously side by side.

By far the bulk of the population is Singhalese Buddhist.  (74% - Wikepedia)  Originally derived from a renegade Indian Prince who landed in Sri Lanka with a band of followers over 2,500 years ago.  They rapidly built up a sophisticated agrarian economy and culture. 

Please see www.everyculture.com/Sa-Th/Sri-Lanka.html & Wikepedia for an excellent study on Sri Lankan history and economy.

Living in Sri Lanka is a wonderfully enriching experience where we can learn totally different ways of seeing life and the world.  We also learn patience ;-)