The index was created by the Institute for Economics and Peace, a non-governmental organization with headquarters in New York and Sydney, Australia. It claims its mission is to focus on positive and achievable measures of human progress, and the methodology of its index centers on 22 indicators that include a country's military expenditure, respect for human rights and level of democracy.
It uses data from an assortment of sources that include the World Bank and the International Institute of Strategic Studies, as well as various United Nations agencies.
According to the index, the world's top ten most peaceful countries, out of 162 rated, are: Iceland, Denmark, Austria, New Zealand, Switzerland, Finland, Canada, Japan, Belgium and Norway.
The United States came in at 101, the United Kingdom was 47th, with Cuba at 75, China at 108, Iran at 131, and Russia at 152.
The five least peaceful countries, the index said, are, in order: Somalia, Iraq, South Sudan, Afghanistan, and in last place, Syria.