The statistics showed that men earned an average of €21 an hour in 2017 while women made just €16.59 an hour on average.

The office said the gap was partly explained by where women and men tend to work, as well as fewer numbers of women in management positions and more women in part-time jobs.

There is also a clear geographic differential in Germany, with the overall gap is roughly three times as big in western Germany, at 22%, than in the east where it is 7%.

Women working in the public sector in the US earn 10% less than men, an analysis found last month. At the start of the year, Iceland became the first country to make it illegal to pay women less than men in the fight against gender discrimination.

In Europe, the average hourly pay of women is 16.3% lower than that of men, the equivalent of women working for free for two months of the year, the European Commission said in November.

The OECD also called for advanced economies to do more to close gender gaps, despite increased focus on getting women into public and private sector leadership.

Simone Rensch has looked at the benefits of gender budgeting and achieving equality through fiscal policy for Public Finance International.