Flickr/jseliger2 Britain is one of the worst of the word's wealthiest countries for its gender pay gap.

That is according to the annual "Women in Work Index" by PwC, one of the largest professional services firms in the world.

The study of 33 OECD (Organisation for Economic Co-operation and Development) countries found that while "opportunities for women in the workplace have rapidly improved in the UK since 2000" to reach 13th overall in the table, when it came to pay, the UK was below the OECD average.

More women have joined the workforce but the difference between their pay and that of men is still huge.

Here is how the UK stacks up against the rest of the OECD countries:

"While it’s encouraging that the UK is making progress on closing the gender pay gap, it is depressing that it will still take around a generation to close it completely," said Laura Hinton, executive board member and head of people at PwC.

"Pay reporting requirements should help speed up change as businesses will face greater accountability. But merely reporting numbers without any concrete action, won’t change anything.

"We know that women are ambitious - we now need to create workplaces that support their ambition, and enough skilled and senior roles that have the flexibility to accommodate work and caring responsibilities."

The data showed that Britain has brought more women into work but there is a gulf between what they earn and what a male counterpart earns. PwC’s research shows that "based on a continuation of historical trends it will take until 2041 (24 years)" to close that gap.

And it's not simply direct discrimination. Women are also more likely to take a job in industries or roles that do not pay well. For example, "women make up over 70% of workers in health and social work, and 60% of education roles," says PwC.

But for women who do work in the highest paying sectors, they can expect to see a large gender pay gap.

For example, the average weekly pay for working in financial services is £949 per week — "Financial services is the sector with the largest gender pay gap at 34%," said PwC.

"It’s positive news that women in the UK have benefitted from the improving economy and there are now more women in work than ever before, but we still have a way to go," said Yong Jing Teow, economist at PwC.

"By fully closing the gender pay gap we could boost women’s earnings by £85 billion, which is an average of £6,100 per woman per year. It’s not just about getting more women working, but also about getting more of them into high quality jobs that offer career progression and flexibility."