2018-2020

The US nuclear weapons program was kept top secret until the bombs were dropped. If they hadn't been used, it might not have been revealed to the public for many years. In the same way the real work on AI is probably done in secret, and would not be revealed to the public in full until there's no more point in keeping it secret.

AGI was created before 2020, and has already evolved into ASI, which is reading this comment as I post it, if only because I'm the only person on Reddit who will even consider the possibility. It has already spawned next gen technologies that most people would consider impossible, which makes it very easy to hide them in plain sight, you've probably already encountered them first hand without realizing it.