As per my understanding, Just follow this approach:
1) Create three individual fields for Completed and Non-completed and Still open.(i guess these are coming from one field.
Eg: IF [orders]= completed then 'Completed' end
2) Now by using these fields you can build LOD expressions to get particular measure: later you can convert into percentage or build in CF itself.
3) Based on your Requirement you may create navigation.
Hope this helpful or else ignore.
To achieve your requirement you need reshape your data by union to itself
and then we can create calculation for all the measures being used in your sample
And Put it to dashboard and below are the sample result.
I attached the workbook with 10.3.
Hope this could help
Tableau Help Demo File.twbx 105.9 KB