On Monday, around 2:38 PM, thousands of women left work early and headed to Austurvollur square in the Icelandic capital of Reykjavik. Punctuality mattered: They were trimming a typical 9-to-5 workday by precisely two hours and 22 minutes, or around 30 percent. Thirty percent also happens to be the gap in average annual income for men and women in Iceland; for every dollar a man makes, a woman makes 72 cents (other ways of measuring the gender wage gap in Iceland yield smaller percentages, and the gap narrows when considering men and women who do the same sort of work). Those assembled at Austurvollur shouted Ut, or “Out,” to discrimination against women. They were essentially saying: If I were a man, I might have earned my paycheck by now, so I’m taking the rest of the afternoon off and demanding change.

The protest put a complex issue into the simple terms of hours and minutes. We’re all intimately familiar with the workday; it’s how many of us mark time. And we can all appreciate how early in the day 2:38 PM is—especially if you’re living in Iceland and women suddenly leave offices and stores and schools en masse. One father who had to pick up his daughter from preschool before 2:38 told the public broadcaster RUV that he supported the demonstration despite the inconvenience. “She should get a better salary in the future like the men,” he explained, as he held his daughter in his arms.

We can also easily translate the lesson across cultures. If women in the United States had staged the same protest, for example, they would have left work at 2:12 PM. In South Korea, it would have been 12:36 PM. In Pakistan, 10:50 AM.

Plus, since women’s-rights organizations and labor unions in Iceland have organized the demonstration in the past, we can actually measure, in minutes, the country’s advances on pay equity. On October 24, 2005, women in Iceland left work at 2:08 PM. On October 24, 2010, they departed at 2:25.

It’s encouraging that progress has been made. But the pace of that progress is dispiriting nonetheless. On Monday, women in Iceland left work only half an hour later than they did 11 years ago. If “the same trend continues,” Vala Hafstad writes in Iceland Review, “not until 2068 will women and men enjoy equal pay.”

The struggle, moreover, began well before 2005. On October 24, 1975, 90 percent of women in Iceland—that’s nine with a zero after it—went on strike to campaign for equal rights. The BBC has more on that extraordinary day:

It is known in Iceland as the Women’s Day Off, and [Vigdis Finnbogadottir, Iceland’s first female president] sees it as a watershed moment. ...

Banks, factories and some shops had to close, as did schools and nurseries—leaving many fathers with no choice but to take their children to work. There were reports of men arming themselves with sweets and colouring pencils to entertain the crowds of overexcited children in their workplaces. Sausages—easy to cook and popular with children—were in such demand the shops sold out.

It was a baptism of fire for some fathers, which may explain the other name the day has been given—the Long Friday.

“We heard children playing in the background while the newsreaders read the news on the radio, it was a great thing to listen to, knowing that the men had to take care of everything,” says Vigdis. …

“Things went back to normal the next day, but with the knowledge that women are as well as men the pillars of society,” she says. “So many companies and institutions came to a halt and it showed the force and necessity of women—it completely changed the way of thinking.”

Yet here Iceland’s women were, in Austurvollur square exactly 41 years later, yelling Ut. What’s most sobering about Monday’s rally is that it occurred in what is arguably the most gender-equal nation on earth. Iceland has had either a female president or a female prime minister for 20 of the last 36 years. Every year for the last eight years, Iceland has finished first among 100-plus countries in the World Economic Forum’s annual Global Gender Gap ranking, which quantifies disparities between men and women in health, politics, education, and employment (the higher a country’s ranking, the smaller its gender disparities).

In its latest report, released on Wednesday, the World Economic Forum noted that while Iceland has become the world leader on measures of political empowerment and educational attainment, it has yet to close gaps in earned income and wages for similar work. (Both of these metrics are important because the gender pay gap is frequently less the result of unequal pay for equal work than of women entering different professions from men and occupying fewer high-level positions.) Iceland is still way ahead of most countries on pay equity, but it hasn’t solved the riddle of how to make the workplace more just.

More broadly, the report found that global progress toward economic parity between men and men has suffered setbacks in the past few years—and that the gap might not close for another 170 years!—largely because of chronic gender imbalances in salaries, labor-force participation, and representation in senior positions. “We’re now hitting a bit of a wall” in terms of policy reforms to address these imbalances around the world, Saadia Zahidi, one of the report’s co-authors, told The Guardian, and sluggish economic growth in many countries isn’t helping.

In The Guardian this week, Noreena Hertz puzzled over why the gender pay gap has persisted in Iceland despite the government’s many policies to eliminate it, including generous paid leave for new mothers and fathers, state-subsidized childcare, and gender quotas for corporate boards. “Explanations vary,” she wrote, “from women going into less well-paid professions, to the penalty paid for working part-time that we’ve found in the UK as well, to the time it takes for employers’ implicit gender biases to shift.”

That time, however, can seem excruciatingly long. As Gylfi Arnbjornsson, the president of the Icelandic Confederation of Labor, told RUV, “No one puts up with waiting 50 years to reach a goal. It doesn’t matter whether it’s a gender pay gap or any other pay gap. It’s just unacceptable to say we’ll correct this in 50 years. That’s a lifetime.”