Dear,
Its very focused query.
First of all you have to check that how many department in your organization/co.
Then you have to check how many designation over there.
Then according to your organization's performance in last three years, you have to analyse about the per year cost already your organization is being spent for HR activities.
Please do remember that in these activities you'll include entire function you are doing in HRD.
Accordingly you can frame the same for current year and next year as well.
Rgds