On the supply side, changes in the age composition of earlier to more recent birth cohorts has led to an exogenous change in the supply of education because, on average, members of more recent birth cohorts that are entering the labor force have more education than members of earlier birth cohorts that are leaving the labor force—holding fixed the within cohort mean education, changes in the cohort composition measure changes in relative supply of education
Changes in recent generational work force is due to them having more access to educational resources.