A running total tells how many parcels have arrived so far, while a rate tells...

https://wiki-nest.win/index.php/If_It_Rains_at_6_mm_per_Hour_for_2_Hours,_How_Much_Rain_Is_That%3F

A running total tells how many parcels have arrived so far, while a rate tells how fast they arrive. Compare 120 parcels by noon with 15 parcels per hour, and see why the units and time window matter when reading a work chart at a glance.