Hillary Clinton, in an essay that published this week, cautions that opportunities for American women could vanish if the U.S. does not prioritize their economic advancement.

“[F]ighting to give women and girls a fighting chance isn’t just a nice thing to do. It isn’t some luxury that we only get to when we have time on our hands. This is a core imperative for every human being in every society,” Clinton writes in “The Shriver Report: A woman’s nation pushes back from the brink,” a report that features essays compiled by Maria Shriver and the Center for American Progress.

Clinton warns that American women lag behind other first-world countries in a slew of important attributes, including life span, equal pay and employment opportunities.

“In places throughout America large and small, the clock is turning back,” says Clinton, noting that while women now hold approximately half of U.S. jobs, the country doesn’t crack the top 10 rankings of countries where women thrive economically.

Women earned about 81 percent of males’ median wages in full-time jobs in 2012, according to the Bureau of Labor Statistics’ annual report released in October. That’s an increase from 62 percent in 1979, the first year comparable data was available. The BLS says women who never married earn nearly 96 percent of a man’s wages; married women take home considerably less, at 77 percent.