Dear Student,
The Sinhala or Sinhalese (74%) constitute the major ethnic group; the Sri Lankan Tamils, who inhabit the north and east form 12.6% and the group known as Indian Tamils (19th century migrants for work on plantations) 5.6% of the population. While Muslims constitute the third largest ethnic group (7.4%), there are also small minorities such as Burghers (people of mixed decent), and Malays.
Regards