I knew you'd say that, but the development of such missiles is probably not a secret.
As for the dates:
https://en.wikipedia.org/wiki/Nuclear_weapons_testing
I don't think the date of the last test tells us a lot though, especially not about the missiles used to deliver the warheads.Underground tests in the United States continued until 1992 (its last nuclear test), the Soviet Union until 1990, the United Kingdom until 1991, and both China and France until 1996. In signing the Comprehensive Nuclear-Test-Ban Treaty in 1996, these states have pledged to discontinue all nuclear testing. However, as of December 2013, the treaty has not yet entered into force because of failure to be signed/ratified by eight specific countries. Non-signatories India and Pakistan last tested nuclear weapons in 1998.
And you conveniently ignored that US warheads are also largely rotting in some bunkers.
While one could argue the US are rebuilding and modernizing their nukes: https://next.ft.com/content/14bcff98...b-fc683b5e52db
This article makes Russia look more ready to use it: http://time.com/4280169/russia-nuclear-security-summit/
Also this: http://www.bbc.com/news/world-us-canada-35845232
Oh yeah: https://www.youtube.com/watch?v=1Y1ya-yF35g
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