Need help calculating the percent different between two columns

Summary

Need help calculating the percent different between two columns

Content

We are creating a recruiter scorecard in OBI. I've used a CASE WHEN formula to enter in each recruiter's individual hiring goal:

CASE

WHEN "Requisition Recruiter"."Recruiter Name" = 'XX' THEN '18'

WHEN "Requisition Recruiter"."Recruiter Name" = 'XX' THEN '27'

WHEN "Requisition Recruiter"."Recruiter Name" = 'XX' THEN '18'

WHEN "Requisition Recruiter"."Recruiter Name" = 'XX' THEN '18'

ELSE 'Other'

END

We have another column that shows actual hire starts:

FILTER("Candidate Counts"."# Submissions" USING ("Submission Dates"."Hire Start Date" BETWEEN timestamp '2016-01-01 00:00:00' AND timestamp '2016-12-31 00:00:00'))