I can easily seen how that figure can obtained as a mean average. In 2010-11 my ILA was 75 days, comprising:
38 days Annual Leave Allowance (ALA)
15 days carried over ALA
1 day Authorised Absence (IIRC that was the Flt Lt's Wedding holiday)
21 days PODL.
On top of that I had 5 days relocation leave.
Of course there is a difference between a leave allowance and the amount of leave taken.