Comparison of proportion of registrants by region of residence preregistry and postregistry expansion
| Pre-expansion (%) | Postexpansion (%) | P value | |
| Central region | 70.2 | 48.1 | <0.01 |
| Eastern region | 12 | 11.6 | 0.73 |
| Northern region | 5.4 | 20.7 | <0.01 |
| Western region | 12.3 | 19.6 | <0.01 |