Violence and worsening conflict cost the world more than $13.6 trillion last year, according to an annual study of the toll of violence worldwide. That figure amounts to some 13 percent of global GDP.

The analysis can be found within the Global Peace Index 2016 report, which is put out each year by the Institute of Economics and Peace, an Australia-based think-tank. It ranked 163 countries on the degree of peace within their borders. The results since the initiative began are not encouraging: "The last decade has seen a historic decline in world peace, interrupting the long term improvements since WWII," a press release indicates.

Moreover, peace and safety, like the incomes of the rich and poor, are growing more unequal, with prosperous, relatively harmonious countries improving, according to the index, and countries already wracked by conflict and violence getting worse. An image from the report's precis charts this trend:

The five most precipitous declines don't even include Syria, which is in the grips of a brutal five-year civil war that has killed more than 250,000 people and triggered an unprecedented regional refugee and security crisis.

“The historic 10-year deterioration in peace has largely been driven by the intensifying conflicts in the [Middle East and North Africa],” says the report. “Terrorism is also at an all-time high, battle deaths from conflict are at a 25-year high, and the number of refugees and displaced people are at a level not seen in 60 years."

The estimated cost of conflict to the world's resources in 2015 is a tabulation based on military spending, the damage caused by conflict, and losses from crime and interpersonal violence. The report stresses how disproportionately greater such security spending is compared to global efforts to build and preserve peace.

You can read more about the report, and its methodology, here.