How the condition of stability in China today compare with that of the 19th century (1800s)

How does the condition of stability in China today compare with that of the 19th century (1800s)?
How does the condition of stability in China today compare with that of the 20th century (1900s)?
What is Pinker’s thesis about the change in violence over time?
To what does Pinker attribute the decline in civil wars and civil unrest?