calculate field pivot table

[MOSHE_AR]

hi,
i try to made calculate field un my pivot table but i didnet get a value ,

i want calculate the percentage of the deliveries that are delayed
i.e.
The number of deliveries that were delayed is divided by all the deliveries that left

look at the attached picture

calculate field pivot table

 

[mrshl9898]

Should be something like =SUM(delayed)/SUM(deliveries) with your correct names