Thank you. I see its data from SalaryExplorer, but I couldn't find where SalaryExplorer source.

Caixin (link, but chinese) did a study last year,

Low-income households, comprising about 300 million people, will have a per capita disposable income of 8,333 RMB in 2021, or 694 RMB per month.

while lower-middle-income households will have a per capita disposable income of 18,446 RMB or 1,537 per month.

High-income households, which make up 20 percent of the population, have a per capita disposable income of 85,836 in 2021, or 7,153 RMB per month.