As of 2016, there are about 1.34 million millionaires in China. That’s just in China. There are probably quite a few that started in China but had moved out by the time that survey was taken. China has a population in the billions, so it’s a good percentage - about 9.7% of the population at the time.
This is because China has an odd economy. To get anything done, businesses have to grease the wheels. Locals have to grease the wheels for favorable policies. Corruption is rife in China’s government, and it doesn’t help that the government has purposefully passed many laws that favor Chinese businesses and promote intellectual theft. As long as the CCP can show that they’re doing a great job, anything is game.