Adding Leave Entitlements for earlier dates

Hi,

I created a policy with the below information:

Policy Name: FT Annual Leave
Days: 20
Department: All Department
Role: All Roles
Location: All Location
Gender: All
Marital Status: All
Effective Date: 2016-11-01 (same as company start date)
Activate: Manually

When I try to add it to an employee entitlement the leave period options are only

01-01-2018 – 31-12-2018
01-01-2019 – 31-12-2019

How can I add older leave policies, as we are trying to backdate all our information from 2017 as well? We need Leave Period from 01-01-2017 – 31-12-2017