1. Physical Activity Guidelines for Americans;US Department of Health and Human Services,2018
2. CDC 2019. Summary Health Statistics: National Health Interview Survey: 2018. Table A-4a. http://www.cdc.gov/nchs/nhis/shs/tables.htm, 2019.
3. CDC 2019. Health United States, 2018. Table 26. https://www.cdc.gov/nchs/data/hus/hus18.pdf, 2019.
4. Tables of Summary Health Statistics for U.S. Adults: 2017 National Health Interview Survey;Blackwell,2018