Blau and Kahn (2000) provide a good summary of the gender pay findings for the US from the mid-1970s. The gender pay gap for full-time employees decreased between the late 1970s and the early 1990s, with a plateau from the mid-1990s. An analysis of 10-year age cohorts found that the gender pay gap tended to decrease for most cohorts over time, indicating that each new cohort of women entering the workforce fares better economically than the previous cohorts. There are also indications that the gender pay gap increases when the cohort reaches the 35-44 years band, rising again in the next band. This suggests that the wages of women in full-time employment are penalised during the child bearing and rearing years. The segregation of women across occupations has also decreased, by similar levels between 1970 and 1980, and between 1980 and 1990. Most of the decrease was due to the movement of women into male-dominated occupations, especially into the male service and white-collar occupations rather than blue-collar jobs. This reduction of occupational segregation continued in the 1990s, but at a slower pace.
Other factors that helped reduce the US gender pay gap included women's increased human capital (education and work experience) and wage convergence, with women receiving a higher increase in indexed wages compared to men between 1978 and 1998. For both genders, wage inequality (as measured by the standard deviation of the natural log of wages) also increased between 1978 and 1998, at approximately the same rate.
Fortin and Lemieux (1998) examined the gender pay gap for the period 1979 to 1991. They found a convergence in the skew of the male and female wage distributions, suggesting that the gender pay gap did not decrease at a uniform rate across the wage distribution. An analysis of the gender pay gap by percentiles, for 1979 and 1991, showed that the gender pay gap decreased more for the 40th to 75th percentiles. The gender pay gap was smallest, for both periods, below the 25th percentile. The relative position of women improved due to increased female labour market experience and improvements in log wage position relative to men.