TOTAL Calculation

month tracking no_count
jan 500
feb 300
march 250
Total. 1050
this is a sample table, what i am trying do is finding overall percentage for each month by creating a calculated field overall_percentage for example for jan =(500/1050)*100
instead of using total value directly i am trying to apply this formula here TOTAL(distinct_count({tracking_number}). but it says its not supported. can you provide any other option to do this