PTBT went into effect, more than 100 states had joined the treaty as signatories and 39 had ratified or acceded to it. The most recent party to the PTBT is Montenegro, which succeeded to the treaty in 2006. , 126 states were party to the treaty, with 10 other states having signed but not deposited instruments of ratification. There are 60 states that have not signed the PTBT, including the nuclear states of China, France, and North Korea. Albania, an ideological ally of China during the PTBT's enactment, also has not signed. Effectiveness The PTBT's ratification coincided with the beginning of a steep decline in the amount of radioactive particles in the atmosphere (following the "bomb spike" in the early 1960s), but it did not halt nuclear proliferation. One year after the PTBT's entry into force, the nonsignatory China conducted the 596 test and became the world's fifth nuclear power. Since China, four other states are known or believed to have acquired nuclear weapons. However, the PTBT has been credited with slowing proliferation because of the greater expense associated with underground tests. Kennedy had warned in 1963 that without a test ban, there could be 10 nuclear states by 1970 and 15 to 20 by 1975. The decade following ratification of the PTBT (1963–1972) featured more US nuclear tests than the decade prior (1953–1962). In the following decade, the US conducted 385 nuclear tests and 23 peaceful nuclear explosions (PNEs), as opposed to 268 tests and three PNEs in the prior decade. In contrast, the number of Soviet detonations fell from 218 in the preceding decade to 157 in the following decade, as the Soviet Union was never able to meet the pace of US underground explosions. China and France, both nonsignatories, conducted 53 tests between 1963 and 1973. In all, 436 tests were conducted between the signing of the PTBT and 1 July 1973, compared to 499 tests between 16 July 1945 and the signing of the PTBT. In the 1960s and the 1970s, China conducted 22 atmospheric tests and France conducted 50. The last atmospheric test was conducted by China in 1980, after French atmospheric testing stopped in 1974. Public opposition to nuclear testing continued after the treaty's enactment. Greenpeace was founded in 1971 in opposition to a planned underground test on the Alaskan island of Amchitka. In 1982, a Greenpeace ship docked at Leningrad without permission to