You need enough people to be able to overcome the military and law enforcement. So that differs depending on the country.

The USA has 2.81 million service members, so nearly 1% of the population. I'd say that one soldier with training and incredible amounts of war machinery could easily take out 10 untrained average americans even if they have guns, so 10% is likely not enough. Might be enough in a country with no money and hardly any military, but just think about it. How many angry people does it take to take out a tank or a fighter jet?