The European Commission defines the gender pay gap as the average difference between men's and women's aggregate hourly earnings. The wage gap is due to a variety of causes, such as differences in education choices, differences in preferred job and industry, differences in the types of positions held by men and women, differences in the type of jobs men typically go into as opposed to women (especially highly paid high risk jobs), differences in amount of work experience, difference in length of the work week, and breaks in employment. These factors resolve 60% to 75% of the pay gap, depending on the source. Various explanations for the remaining 25% to 40% have been suggested, including women's lower willingness and ability to negotiate salaries or else due to discrimination. According to