Dutch one-man firms generate turnover of some €62.5bn a year towards the economy, equivalent to 10.2% of national GDP, according to the latest edition of the ZZP Barometer.

The survey, based on a representative sample of almost 1,500 people, shows freelancers (ZZP’ers in Dutch) earn an average of €68.18 per hour. The Netherlands has some one million freelancers and interims, ZZP Barometer says.

Of the time freelancers spend on their company, 894 hours are billable to clients, resulting in average annual profit of €37,000, the Barometer says. Women bill some 25% fewer hours than men.

The ZZP Barometer was set up in 2009 and aims to provide independent facts and figures about the self-employed. It is sponsored by a variety of companies, from banks to staffing agencies.

However, a survey last month by freelancer website Hoofdkraan.nl said freelance pay rates are coming under increasing pressure.

On average, a freelancer now charges €44 an hour, down €1 on a year ago. Project managers, coaches and support staff are the highest paid, while translators, sales staff and secretaries earn an average of €35 an hour, the website said.