Forum Discussion
Pivot table average
I could be wrong, but based on you screenshot
you are on Excel desktop for Windows.
Power Pivot add-in is still available for download for Excel 2010 Download Microsoft® SQL Server® 2012 SP1 PowerPivot for Microsoft Excel® 2010 from Official Microsoft Download Center, I guess for Excel 2013 it exists as well. Starting from Excel 2016 Power Pivot is built-in, the only it shall be activated in Options. In general only data model is required, measures could be created without Power Pivot.
However, if you are on Android, Mac or web - Power Pivot is not available.
Perhaps something could be done with VBA if to use cached PivotTable, but I'm not sure.
If nothing of above is available, perhaps to use some other tools/formulae in addition or instead of PivotTable.