Percentage increase is the change in the value when it is increased over a period of time. Population increase and increase in the literacy rate are examples of percentage increases. On the other hand, a percentage decrease is a change in the value when it is decreased over a period of time. Decrease in the level of covid-patients or decrease in the rainfall rate are examples of percentage decreases.
There are some steps that you should keep in mind while solving a question on
percentage increase or decrease.