Eurostat

Eurostat collects information on the wages across Europe. This site offers a brief overview of gender pay gap (GPG) statistics, including the unadjusted gender pay gap used to monitor imbalances in earnings between men and women. The unadjusted gender pay gap is defined as the difference between the average gross hourly earnings of men and women expressed as a percentage of the average gross hourly earnings of men. It is calculated for enterprises with 10 or more employees.

Read here: http://ec.europa.eu/eurostat/statistics-explained/index.php/Gender_pay_gap_statistics