Unadjusted gender pay gap is a significant indicator, showing 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 does not take into account education, age, hours worked or type of job.
It's a significantly bad indicator for being unadjusted. The assumption it leads to is for people working in the same position, with the same amount of experience, and working the same amount of hours, there is a gap in wages reaching sometimes 20%, but that simply is not the average case.