It used to be that no matter the hours the CEO kept, rank-and-file workers generally received a set amount of paid vacation, paid sick days, and paid maternity leave because unions successfully bargained for these guarantees. (And many nonunion companies embraced those provisions as well to help keep the unions out.) Over the last half-century, however, the proportion of U.S. workers in unions has shrunk from 35 percent to 12 percent overall, and just 7.5 percent in the private sector.