June 21, 2018
July 16, 2010
The problem is caused by the incorrect data layout for a PivotTable. PivotTables require tabular data, and that means, among other things, a single row of column headers. You need to fix the nested column headers, which you can do using Power Query, as explained in my Power Query Unpivot video tutorial.
In the attached file I've added some dummy values to your table so it's useful for answering your question. I've used Power Query to fix your nested column headers.
I hope that points you in the right direction.