Wages: Men vs Women

...The Wages Gender Gap;  Women are almost half of the workforce. They are the equal, if not main, breadwinner in four out of ten families. They receive more college and graduate degrees than men. Yet, on average, women continue to earn considerably less than men. In 2015, female full-time workers made only 80 cents for every dollar earned by men, a gender wage gap of 20 percent. Women, on average, earn less than men in virtually every single occupation for which there is sufficient earnings data for both men and women to calculate an earnings ratio. In middle-skill occupations, workers in jobs mainly done by women earn only 66 percent of workers in jobs mainly done by men. 

If change continues at the same slow pace as it has done for the past fifty years, it will take 44 years—or until 2059—for women to finally reach pay parity.   Why?????