As recent Eurostat figures show, female employees in Switzerland earn 19.3 percent less than their male colleagues, worse than the European average of 16.4 percent.
Now London-based business comparison site Expert Market has mapped gender pay gap data from 40 European nations to show exactly when in the year women effectively start working for free.
Switzerland ranks 30th in the table, with only ten countries having a larger gender pay gap, including the UK, Germany and Austria, whose female workers all started grafting for free earlier this month.
At the bottom of the table with a 46 percent pay gap, Bosnian women effectively had no salary from July 15th.
Slovenia topped the table, with only a 3.2 percent gender gap, followed by Malta, Poland, Norway and Italy in the top five.
Source: Expert Market
“It's the 21st century, so seeing such wage gaps is shocking considering the opportunities for both men and women,” Expert Market researcher Tom Watts told The Local.
"There's a very deeply entrenched mindset, Europe wide, about the female employee. People still tend to think that the woman stays at home and looks after the family while the man goes out and works, and that is reflected in the wage gap we see,” he added.
Such attitudes are particularly prevalent in Switzerland, according to Vivian Fankhauser-Feitknecht of Alliance F, an umbrella organization for women's associations in Switzerland.
“The problem of gender stereotypes continues to be widespread in Switzerland,” she told The Local.
“There is still a lack of strategic involvement from the media on this matter and the topic does not receive sufficient attention in schools.”
“Career choices are still very much determined by patterns that are influenced or prescribed by society. Women's working lives are characterized by unpaid work, career interruptions or part-time work.
“One reason is the difficulty of reconciliation of work and family life,” she said, adding that, since women's salaries are lower, it usually falls to them to stay home to care for their children, rather than men, thus exacerbating the wage gap.
In terms of changing such patterns, progress is still slow in the country, said Fankhauser-Feitknecht.
“The awareness-raising measures taken to date have had little impact. Successes are still only visible in those areas where the state imposes mandatory measures,” she told The Local.
To help combat the gender pay gap, companies should be required by law to carry out wage monitoring and publish the results, she said.
And a wage commission should be established to carry out spot checks, a move which would help ensure transparency in pay-related matters.
In 2015 former Swiss presidents Ruth Dreifus and Micheline Calmy-Rey were among those signing a manifesto calling for pay equality and a higher representation of women in the boardroom of companies operating in Switzerland.
And in September this year ten cantons signed a charter vowing to combat salary inequality in public sector jobs through wage monitoring.
The government is also debating a proposed scheme to reduce the burden of childcare costs on families in an attempt to remove the financial barriers for women who want to return to work.
But no progress has been made when it comes to parental leave. Proposals for paternity leave or shared parental leave have been repeatedly defeated in parliament.