The annual index of the Washington non-profit and non-partisan organization, founded in 2001 by media mogul Ted Turner and former U.S. Sen. Sam Nunn, is an assessment of nuclear materials security conditions in countries around the world.
"We need a global nuclear materials security system to secure all materials ... to hold each other accountable," said Nunn, the initiative's co-chairman.
The report noted seven countries --– Austria, Czech Republic, Hungary, Mexico, Sweden, Ukraine and Vietnam -- have removed all or most of their stocks of weapons-usable nuclear materials from their territories.
The report analyzed conditions in 176 countries, the majority without nuclear armaments but possible safe havens or staging grounds for nuclear materials. Australia ranked first among 25 countries with weapons-usable nuclear materials, but the report noted Australia has reduced its stock of materials since 2012, and ratified an international agreement calling for criminalization of acts of nuclear terrorism.