| 2015 | 2016 | 2017 | 2018 | ||||
---|---|---|---|---|---|---|---|---|
χ2 | P | χ2 | P | χ2 | P | χ2 | P | |
Gender (Chi square test) | 8909.00 | P < 0.0001 | 9941.90 | P < 0.0001 | 11,004.00 | P < 0.0001 | 12,836.00 | P < 0.0001 |
Marital status (Chi square test) | 94.67 | P < 0.0001 | 109.88 | P < 0.0001 | 58.18 | P < 0.0001 | 152.38 | P < 0.0001 |
 | Z | P | Z | P | Z | P | Z | P |
Educational level (Cochran-Armitage test) | 10.22 | P < 0.0001 | 17.88 | P < 0.0001 | 20.78 | P < 0.0001 | 16.34 | P < 0.0001 |