You can use this formula to determine percentage increase:
100(New Value - Old Value)/(Old Value)
Example: There were 200 customers yesterday, and 240 today:
100(240 - 200)/200 = (40/200) * 100 =
20% increase.
20% increase.
Example: But if there were 240 customers yesterday, and 200 today we would get:
100(200 - 240)/240 = (-40/240) × 100% =
A 16.6...% decrease.
A 16.6...% decrease.