Custom coefficient calculation based on jira data

[Ходырев Иван (Server)]

I have a task to calculate custom coefficient for each person in my department. 
The formula is as follows:
coefficient=sum_estimates(person,month) / (work_time(person,month) - sum_worlog_times_in_task_x(person, month, taskId))

where 
sum_estimates(person,month) - sum of estimates of closed tasks for a particular person in a particular month

work_time(person,month) - working time for a person (actually this data should not be taken from jira and will be a constant when calculation occurred, but it have to be different for each person)

sum_worlog_times_in_task_x(person, month, taskId) - sum of work log times of a particular person to a task with a particular taskId in a particular month.

What is the best way to implement such calculation in Jira and probably to make some kind of report which calculates everything automatically?

[Gezim Shehu [Communardo]]

Depends on where would you like to display this.

Report only (get data from db or rest service), confluence(integration), jira itself (not sure how to best implement this)