You can create a rate of change or percentage rate of change chart in a couple of clicks in DataHero.
Drag on a date property and a numerical value.
Rate of Change Chart
Click the icon with two arrows pointing in opposing directions (comparison button) in the top right of the chart canvas for a rate of change chart.
Percentage Rate of Change
Click both the percentage (top left of chart canvas) and comparison buttons for a percentage rate of change chart.