Martin JA, Hamilton BE, Osterman MJK, Driscoll AK. Births: Final Data for 2020. National Vital Statistics Reports; vol 70 no 17. Hyattsville, MD: National Center for Health Statistics; 2022. (Table I-4 available from: https://www.cdc.gov/nchs/data/nvsr/nvsr70/nvsr70-17-tables.pdf.)