variable

unit

1997

2000

2004

2006

2009

2011

Mean standard deviation

Mean standard deviation

Mean standard deviation

Mean standard deviation

Mean standard deviation

Mean standard deviation

Education years

years

9.210

9.610

10.55

10.68

10.46

11.25

(3.080)

(3.041)

(2.958)

(3.189)

(3.177)

(3.274)

Working years

years

20.11

20.36

21.88

22.70

23.21

22.32

(10.84)

(10.88)

(10.15)

(10.21)

(10.09)

(10.08)

Monthly salary

yuan

376.8

422.4

668.5

917.0

1513.3

1959.2

(441.4)

(816.4)

(1737.9)

(2202.9)

(3326.0)

(3545.3)

Llogarithm of

5.946

6.229

6.587

6.785

7.183

7.560

monthly wages

(0.565)

(0.605)

(0.583)

(0.624)

(0.646)

(0.631)

N

2609

2696

1933

2064

2344

3548