The figure below, from Danilo Trisi at CBPP, shows the employment rates (share of the population at work in the paid labor market) of three categories of women: married and never-married moms, and single women without kids.

All the women in the sample are between 20 and 49 and have no more than a high-school degree.

Why these groups?

Because this is an analysis of work-based welfare reform and its interaction with the demand side of the job market.