Female retail workers in the US earn $4 less per hour than their male colleagues, according to a report released this week.

Amy Traub, senior policy analyst at Demos and the author of the report, said that the discrepancy was partly due to the number of women in part-time positions, but also “flat out discrimination”.

“We are hearing a lot about women’s economic advancement recently, from the excitement about the potential of a female president of the United States to exhortations to women to ‘lean in’ in professional jobs,”  Ms Traub said. “But when we look at the most common [female] occupation today, it’s not a high-flying executive. It’s a retail sales person.”