Of the five senators who participated in Wednesday’s press conference—Barbara Mikulski (D., Md.), Patty Murray (D., Wash.), Debbie Stabenow (D., Mich.), Dianne Feinstein (D., Calif.) and Barbara Boxer (D., Calif.)—three pay their female staff members significantly less than male staffers.

Murray, who has repeatedly accused Republicans of waging a “war a women,” is one of the worst offenders. Female members of Murray’s staff made about $21,000 less per year than male staffers in 2011, a difference of 35.2 percent.

That is well above the 23 percent gap that Democrats claim exists between male and female workers nationwide. The figure is based on a 2010 U.S. Census Bureau report, and is technically accurate. However, as CNN’s Lisa Sylvester has reported, when factors such as area of employment, hours of work, and time in the workplace are taken into account, the gap shrinks to about 5 percent.

A significant “gender gap” exists in Feinstein’s office, where women also made about $21,000 less than men in 2011, but the percentage difference—41 percent—was even higher than Murray’s.