Demographic trends are always important to enrolments and participation rates. Unfortunately no data source tells us in total or by age how many people meet the eligibility criteria for a Commonwealth-supported place.
The size of the birth cohort has a significant influence, but under-counts eligible persons due to migration. With 22 per cent of domestic students born overseas migration is important to demand. ABS demographic data includes migrants, but because of long-term temporary residents over-states how many people are eligible for a CSP.
As universities generally require students to have completed Year 12, final year of school enrolments are also a guide to potential demand. However, this is also an imperfect indicator, due to temporary migrants and not all Year 12 students taking subjects that qualify them for university entry.
With all these caveats, the chart below shows that none of the potential population indicators suggest that, holding participation rates constant, that demand for higher education should be up in aggregate terms. The (temporarily) falling size of the birth cohort and the slight dip in Year 12 students would suggest that demand might trend down.