2018

2019

2020

Total

Original observed value

1701

1730

1745

5176

Removed: Companies of the financial industry, the securities industry and the insurance industry

(43)

(43)

(43)

(129)

Less: Companies with incomplete variable data

(634)

(587)

(591)

(1812)

Final observed values of samples

1024

1100

1111

3235