9,,000 of Britain's biggest companies have less than a week to publish their gender pay gap figures, currently just over two-thirds of companies have done so.
With days to go until the 4 April deadline, over 6,000 companies have disclosed the difference between what they pay male and female employees.
Companies who fail to provide their data by next week will face legal action.
According to the data analysis the vast majority of firms pay men more than women.
However, about 13% pay women more on average than men, based on the companies that had reported by 29 March. Some 7% said they have no pay gap at all.
78% OF COMPANIES PAY MEN MORE.
All firms with more than 250 employees in Great Britain must report their gender pay gap by next week's deadline.
The UK has a national median pay gap of 18.4%, according to the Office for National Statistics (ONS).The median is the midpoint.
If you line up all the men and women working at a company in two separate lines in order of salary, the median pay gap will be the difference in salary between the woman in the middle of her line and the man in the middle of his.
It's calculated on an hourly basis and includes both full-time and part-time workers. It's the key measurement used by the ONS.
The size of the gender pay gap varies between sectors.
Just three sectors pay women more than men: the water and waste management sector, household services, and, perhaps surprisingly, mining.
The finance sector has the highest pay gap of all sectors, based on the ONS's latest Annual Survey of Hours and Earnings (Ashe).
The average woman working in the finance sector earns 35.6% less than the average man. Another way of expressing this is that she takes home just 64p for every £1 that her male colleagues earn.
THE FINANCE SECTOR HAS THE BIGGEST PAY GAP
Just eight of the 279 finance companies that have released their data so far have a gender pay gap in favour of women.
Virgin Money reported a pay gap of 38.4% in favour of men, the highest gap among the top players that have reported in the finance sector.
Royal Bank of Scotland has a 36.5% pay gap in favour of men.
This is the first year that British firms have been asked to report their gender pay gap figures, but the UK is not the only country currently shining a light on the issue.
Around the world companies are increasingly being asked to provide the same set of information.
The UK has a higher gender pay gap than both the OECD and EU averages.
South Korea has the biggest gap among OECD countries, and Costa Rica the lowest.
