1997

2000

2004

2006

2009

2011

Intercept

3.265***

3.966***

4.653***

5.255***

5.846***

6.165***

Overeducation

0.023***

0.020**

0.032***

0.073***

0.053***

0.060***

Appropriate education

0.192***

0.157***

0.148***

0.088***

0.054**

0.069***

Education shortage

−0.008

−0.001

−0.042***

−0.020**

−0.024***

−0.025***

Working experience

0.021***

0.020***

0.018***

0.020***

0.018***

0.016***

Empirical square

−0.000***

−0.000***

−0.000***

−0.000***

−0.000***

−0.000***

Take government units as the reference group

Collective economy

0.470***

0.211***

−0.165***

−0.206***

−0.128***

−0.138***

Individual joint ventures

0.148**

−0.077

0.063*

0.097***

0.057*

0.095***

Other

0.519***

0.153

−0.210***

−0.050

−0.230***

−0.064

Taking agriculture and animal husbandry as the reference group

Administrative office

−0.033

0.014

−0.164***

−0.084

0.141**

0.067

Senior technicians

−0.002

0.300***

0.000

0.129**

0.328***

0.249***

General technicians

0.000

0.322***

−0.122**

0.000

0.256***

0.165***

Skilled mechanic

0.379***

0.393***

0.061

0.019

0.049

0.150**

Unskilled mechanic s

0.250***

0.348***

−0.080

−0.118*

−0.042

−0.007

Administration

0.261***

0.502***

−0.187***

0.000

0.142**

0.117**

Service trade

0.391***

0.392***

0.068

−0.129*

−0.074

−0.069

Other

0.400***

0.000

0.139

−0.136*

0.000

0.000

Take women as the reference object

Male

0.200***

0.227***

0.172***

0.248***

0.332***

0.237***

Taking the rural areas as the reference object

Urban areas

0.040*

0.059**

0.096***

0.048*

0.068***

0.081***

Taking the western region as the reference object

Eastern area

0.221***

0.144***

0.197***

0.207***

0.136***

−0.030

Middle area

0.111***

−0.025

0.044

0.108***

0.122***

−0.093***

N

2473

2353

1894

2022

2298

3411

R²

0.155

0.117

0.190

0.209

0.218

0.200