Fully closing the gender pay gap could increase total female earnings by $2 trillion across the economies of the OECD (Organisation for Economic Co-operation and Development) countries, according to the latest Women in Work Index by PricewaterhouseCoopers.

Findings from the index showed that Iceland, Sweden and Norway remain the top three performing OECD countries in the index. Of the total 33 OECD countries, all have shown improvements in absolute terms from last year, with the exception of Finland, Switzerland, Chile and Australia.

Meanwhile, the UK has fallen from the 14th to 15th position. The report added that although it has made strides in female employment prospects, its gains have been outpaced by improvements in female job market conditions and gender pay gap elsewhere. If the pay gap in the UK could be closed, then it could boost female earnings by £90 billion a year, or £6,300 per woman.

According to the index, there are also economic benefits in the long-term from increasing the female employment rate to match that of Sweden’s (61%). The GDP gains across the OECD could be over $6 trillion.

Among other key findings of the report show that Poland recorded the largest annual improvement, rising from 12th to 9th place due to a fall in female unemployment and an increase in the full-time employment rate for women.

Luxembourg has seen the biggest improvement in its rank over the long-term, while Portugal has seen the largest negative movement.

Pwc’s analysis of the drivers of the gender pay gap across the OECD shows that government spending on family benefits, the share of female entrepreneurs, maternity leave and occupational segregation help explain the gender pay gap.

“Government policies to reduce the gender pay gap should focus on enhancing social support to families to help women stay in, or return to work, and promoting female entrepreneurship. Business can also help by improving opportunities for working women in higher-paying, higher-skilled roles through greater flexibility,” the report stated.