The rankings are based on 23 criteria ranging from level of violence and military expenditure to ties between neighbours and respect for human rights.

By these criteria, Iraq is the most violent country in the world, followed by Somalia, Afghanistan, Sudan, Pakistan, Israel and Congo.

The most peaceful countries include New Zealand, Iceland, Japan, Austria, Norway, Ireland, Denmark, Luxembourg, Finland and Switzerland.

The US is placed at 85^th position on the world list of 149 nations, behind Cuba (72^nd), and China (80^th).

The 2010 GPI report says that last year the world became less peaceful, as two thirds of the countries in the list got more riotous than in 2007.

It also says that worldwide peace would save the global economy US$7 trillion each year because peace would enable greater economic accomplishments and smaller expenditures for ensuring security. The money saved could be invested to boost prosperity around the globe.