The Soviet Union had a population larger than the United States' at the time of its collapse. North of 100 million people were liberated virtually overnight from direct Russian rule, from USSR states (over 50 million in Ukraine alone); and another 100+ million from Russian-backed communist governments in Warsaw Pact states (40 million in Poland alone).
British India (three modern states) had a population of 400 million at the time of its independence from Britain. That was famously a coordinated, nation-wide movement.
Indonesia was around 200 million people at the end of the Suharto dictatorship and its transition towards democracy.