Women CEOs earned bigger bucks on average than their male counterparts last year, but unfortunately they are still few and far between at the world's largest companies.

The median pay for a female CEO was $13.1 million last year, up 9 per cent from 2015, according to an analysis by executive data firm Equilar.

By comparison, male CEOs earned $11.4 million - which was also an increase of 9 per cent.

But the number of women in CEO roles has barely budged, meaning they are still drastically underrepresented.

This photo combination of images shows the 10 highest paid women CEOs in 2016. Top row, from left: IBM CEO Virginia Rometty; Yahoo CEO Marissa Mayer; PepsiCo CEO Indra Nooyi; General Motors CEO Mary Barra, and General Dynamics CEO Phebe Novakovic. Bottom row, from left: Lockheed Martin CEO Marillyn Hewson; Mondelez International CEO Irene Rosenfeld; Duke Energy CEO Lynn Good; Mylan CEO Heather Bresch; and Reynolds American CEO Susan Cameron. (AP Photo)

Just 6 per cent of the top paid CEOs in the US last year were women, according to the Equilar and AP analysis, a slight increase from about 5 per cent in 2015 and 2014.

The highest paid woman was Virginia Rometty of International Business Machines, bumping out Yahoo's Marissa Mayer from the top spot.

Rometty earned $32.3 million last year from the technology company, a 63 per cent jump from the year before, mainly due to $12.1 million in stock option awards she didn't receive in 2015.

Mayer earned $27.4 million last year, making her the second-highest paid woman. But she may be out of a job after Yahoo completes the sale of its websites and email services to Verizon Wireless in June.

Virginia Rometty (left) and Marissa Mayer (right) led the field of female CEOs, earning $32.3million and $27.4million

PepsiCo Indra Nooyi (left) was third on the list of earnings with $25.2million, followed by Mary Barra (right) of General Motors with $22.4

The 41-year-old is not expected to join Verizon, and Yahoo has said Mayer will receive a $23 million severance package if she departs.

Third on the list was Indra Nooyi of PepsiCo, the maker of Mountain Dew soda and Lay's potato chips. She earned $25.2 million, up 13 per cent from 2015.

THE 10 HIGHEST PAID FEMALE CEOS 1. Virginia Rometty, International Business Machines: $32.3million 2. Marissa Mayer, Yahoo: $27.4million 3. Indra Nooyi, PepsiCo: $25.2million 4. Mary Barra, General Motors: $22.4million 5. Phebe Novakovic, General Dynamics: $21.2million 6. Marillyn Hewson, Lockheed Martin: $19.4million 7. Irene Rosenfeld, Mondelez International: $15.8million 8. Lynn Good, Duke Energy: $13.5million 9. Heather Bresch, Mylan NV: $13.3million 10. Susan Cameron, Reynolds American: $13.1million Advertisement

She was followed by Mary Barra, the CEO of automaker General Motors, who earned $22.4 million.

General Dynamics' Phebe Novakovic rounded out the top five, and was the last woman to break the $20million mark, with $21.2million.

The lowest paid female CEO, according to Equilar's ranking, was Susan Story of utility company American Water Works, who earned $4.1 million.

To calculate pay, Equilar added salary, bonus, perks, stock awards, stock option awards and other types of compensation.

Equilar only looked at companies in the Standard & Poor's 500 index that filed proxy statements with federal regulators between January 1 and April 30, 2016. And it only included CEOs that have been in their roles for at least two years in order to exclude sign-on bonuses.

Of the 346 CEOs in that group, just 21 were women.

The only black woman on the Equilar list, Xerox's Ursula Burns, left the CEO role in January after the document management company split in two.

Burns, who earned $13.1 million as CEO last year, is now chairman of Xerox's board.

General Dynamics CEO Phebe Novakovic (left) earned $21.2million in 2016, while Marillyn Hewson (right) of Lockheed Martin pocketed $19.4million

Mondelez International's Irene Rosenfeld (left) earned $15.8million last year, and Lynn Good (right) of Duke Energy was paid $13.5million

Heather Bresch (left), CEO of pharmaceutical company Mylan NV, was paid $13.3million in 2016. Susan Cameron (right) of Reynolds American made $13.1million

Gracia Martore, who earned $8.5 million last year, announced earlier this month that she will retire as CEO of Tegna, the TV station owner and operator. Her replacement is a man.

In the wake of the list being released, experts have called on companies to do more to promote women to the most senior spots.

Janice Ellig, the co-CEO of executive search firm Chadick Ellig, said 'unconscious bias' in the workplace is keeping women from getting opportunities that will put them on track to for top roles.

Companies need to 'start recognizing that gender inequality exists,' Ellig, who is also chairperson of the Women's Forum of New York, said.

'If you don't recognize a problem, you can't solve a problem,' she says.

The typical CEO at the biggest US companies received an 8.5 per cent raise last year, raking in $11.5 million in salary, stock and other compensation, according to a new study. This photo shows the top 10 highest paid CEOs in 2016