In its Global Peace Index published in London on Wednesday the Institute ranks 163 countries on the basis of 23 qualitative and quantitative indicators.
According to the index, the world has become less peaceful for the ninth year in succession.
The Tigray conflict in Ethiopia claimed the most victims by far last year. More than 100,000 are reported to have been killed in conflict there over the course of 2022. At least twice as many died as a result of disease and starvation caused by the fighting between the Ethiopian and Eritrean government forces and rebels of the Tigray People's Liberation Front.
The Russian invasion of Ukraine was in second place with at least 82,000 people dying.
Among the indicators taken into account in the Global Peace Index are deaths from internal and external conflict, the murder rate, degree of militarisation, weapons exports, terrorism, political instability and the number of prisoners.
It also estimates the economic costs of armed conflict. Last year those costs reached $17.5 trillion, corresponding to 13 per cent of global gross product.
Iceland topped the list of most peaceful countries with New Zealand second and Australia in 12th place.
Afghanistan, Yemen and Syria were ranked the least peaceful.
