Since the NPT entered into force in 1970, three states that were not parties to the Treaty have conducted nuclear tests, namely
According to Bulletin of the Atomic Scientists Nuclear Notebook 2014, the total number of nuclear weapons worldwide is estimated at 10,144.
Five states are known to have detonated a nuclear explosive before 1 January 1967 and are thus nuclear weapons states under the Treaty on the Non-Proliferation of Nuclear Weapons, they also happen to be the UN Security Council's permanent members with veto power on UNSC resolutions. These nations are the
From a high of 68,000 active weapons in 1985, as of 2016 there are some 4,000 active nuclear warheads and 10,100 total nuclear warheads in the world. Many of the decommissioned weapons were simply stored or partially dismantled, not destroyed.
It is also noteworthy that since the dawn of the Atomic Age, the delivery methods of most states with nuclear weapons has evolved with some achieving a nuclear triad, while others have consolidated away from land and air deterrents to submarine-based forces.