calculate percentage change between current period and year end period - calculated attribute

Summary:

calculated attribute in ARCS

Content (required):

we wants to add a calculated attribute in ARCS.

Requirement is to calculate percentage change between current period balance (Jan-22, Feb-22, Mar-22 and so on) and year end period balance (Dec-21)

Two challenges we are facing 

1. To calculate total period activity from year end period (static for FY 22 - Dec-21) to current period.

2. To fetch year end period balance (Dec-21)

(1) divided by (2) will give a percentage change.

Any ideas on script writing for this requirement.