Gender equality best in Sweden, worst in Greece

"We are still a long way off from reaching a gender-equal society and all countries in the European Union have room to improve," said the institute's director, Virginija Langbakk, in a statement.

The report ranked EU states on an index score from one to 100 in terms of work, money, knowledge, time, power and health between 2005 and 2015. It also probed issues of violence.

The EU average was 66.2, only a slight improvement of 4.2 points when compared to 2005.

With 100 seen as full equality, Sweden posted the best index score at 82.6, followed by Denmark (76.8). Finland and the Netherlands placed a close third best.

Greece ranked at the bottom with 50, followed by Hungary (50.8) and Slovakia (52.4).

Scores had increased in most other member states, except for the Czech Republic, Lithuania, Finland, Slovakia, and the UK where no progress had been made in 10 years.

The report also noted that Bulgaria, Croatia, Hungary, Spain, and the UK were each ranked two positions lower in the index in 2015 than in 2005.

The biggest improvements were seen in Italy (+ 12.9), followed by Cyprus (+ 9.2). Ireland and Slovenia had also improved their scores by 7.6 points each.

Many of those increases were due, in part, to a better balance in decision-making.

But Langbakk said in some areas, gaps between the two genders is now worse than 10 years ago.

The report noted that 12 EU states have slipped backward on housework, for instance. Overall, some 79 percent of women engaged in daily cooking and housework, compared to only one third of men.

Time is also an issue given that by 2015 only nine EU states (Belgium, Denmark, Ireland, Estonia, France, The Netherlands, Slovenia, Spain and Sweden) offered child care for at least 90 percent of children aged between 3 years old and the mandatory school age.

The EU's commissioner for justice, Vera Jourova, noted she intends to propose further measures later this year to address the gender pay gap.

"Equality is not about making women more like men, but about creating an environment where both sexes can have equal choices," she said.

Earlier this month, she pointed out in a tweet how a marathon in Brussels awarded €1,000 to men who placed first, while giving women only €300.