The stats are a bit old (2006 I think) but the defence cadets provide 45% of ADFA entrants. The AAFC (7000 cadets) provided the same number of ADFA army officer cadet entrants as did the army cadets (17000 cadets). One in five ADFA entrants was formerly AAFC.
That said, the organization is shortly in for a significant change that has the potential to remove the significant volunteerism ethos.