Pivot table arrangement

Hello all,

I have hourly data for an entire year, and my first column is the corresponding month (i.e. Jan, Feb …). The next two columns are measured and simulated data.
I have created a pivot table and I can display the average/sum for each month using the pivot table. But when I add another field (i.e. another column) to the pivot table (using change data source) my 12 annual months disappear from the pivot table! (Only 3 remain: May, Jun, Jul). The offending file is attached...

Any suggestion how I could continue to arrange the extended data with 12 months as row entries?
Thanks,

Thanks Dimitrov

Sounds really so simple when it is explained.

Best wishes.