Sources:

Mothers of very young children and the total workforce: American Community Survey 2011-15 five-year averages calculated by NWLC using Steven Ruggles et al., IPUMS: Version 6.0 [Machine-readable database]. Minneapolis: University of Minnesota, 2015. Median hourly wage of occupations (used to determine low-wage occupations): Bureau of Labor Statistics (BLS), Occupational Employment Statistics (OES), May 2015 National Occupational Employment and Wage Estimates, http://www.bls.gov/oes/current/oes_nat.htm.
Average cost of full-time infant care at child care centers: Child Care Aware, Parents and the High Cost of Child Care 2016 Report, Appendix Table 1: 2015 Average Annual Cost of Full-Time Center-Based Child Care by State, http://www.usa.childcareaware.org/wp-content/uploads/2016/12/CCA_High_Cost_Appendices_2016.pdf.
Child poverty rates: NWLC calculations based on U.S. Census Bureau, 2015 American Community Survey, https://www.census.gov/programs-surveys/acs/.
Minimum wages: U.S. Department of Labor, Minimum Wage Laws in the States, January 1, 2017, available at http://www.dol.gov/whd/minwage/america.htm.

Notes:

Mothers of very young children are those who have at least one child age 3 or younger at home. Figures are for all employed workers. “Low-wage” occupations are those with median hourly wages of $10.50 or less per hour.