Ethics approval
Our study did not require an ethical board approval because we used publicly available anonymized data for analyses. The dataset used in this study meet the definition of National Institutes of Health (NIH) Exempt Human Subjects Research under the following exemption criteria: “Exemption 4: involves the collection/study of data or specimens if publicly available, or recorded such that subjects cannot be identified”. The original survey protocol was approved by the institutional review boards of International Institute for Population Sciences (IIPS) and ICF. The survey complied with the U.S. Department of Health and Human Services regulations for the protection of human subjects (45 CFR 46).