Table 1 Covariate summary

Annual earnings^a

Years of labor market experience

Male^b

Member of communist party^b

Employed in manufacturing sector^b

Employed in state-owned enterprise^b

Graduated from college^b

Graduated from college ranked very good^b

Graduated from college ranked good^b

Minority^b

Intellectual youth^b

Anhui Province^b

Beijing Province^b

Chongqing Province^b

Gansu Province^b

Guangdong Province^b

Henan Province^b

Hubei Province^b

Liaoning Province^b

Shanxi Province^b

Sichuan Province^b

Yunnan Province^b