A running total tells you how much has piled up; a rate of change tells you how...

https://tiny-wiki.win/index.php/What_Is_the_Best_Way_to_Compare_Two_Reports_That_Use_Different_Time_Scales%3F

A running total tells you how much has piled up; a rate of change tells you how fast it’s moving. Use parcel counts per hour or rainfall in inches per day to see why units and time windows matter when reading a chart at work.