percentage point

English

percentage point (plural percentage points)

One hundredth of a given value, used to measure the difference of two percentages.
- 2013 August 3, “Boundary problems”, in The Economist, volume 408, number 8847:
  Economics is a messy discipline: too fluid to be a science, too rigorous to be an art. Perhaps it is fitting that economists’ most-used metric, gross domestic product (GDP), is a tangle too. GDP measures the total value of output in an economic territory. Its apparent simplicity explains why it is scrutinised down to tenths of a percentage point every month.
The difference between 20 percent and 30 percent is 10 percentage points, not 10 percent. In fact, an increase from 20 to 30 percent is an increase of 50 percent. Only if, for example, 20 percent of buyers choose a certain company's products in one year and 22 percent do so the next year, can one speak of an increase of 10 percent.

unit of the difference of two percentages