The year-on-year calculation formula is: year-on-year growth rate = (number of periods-number of periods) ÷ number of periods × 100%. To put it simply, the comparison between the nth month and the nth month is mainly used to exclude the influence of seasonal changes, and compare the development level of the same period with that of the current period to see a relative development speed.

In fact, there are two kinds of year-on-year calculation formulas, the first is the year-on-year development speed, and the second is the year-on-year growth speed. These two formulas are different.

It should be noted that the year-on-year development speed = current development level/same period level ×100%; Year-on-year growth rate = (current development level-same period level)/development level × 100%.

It should be noted that some problems are often encountered in practical work or in the process of doing math problems, that is, various indicators will be used, especially when doing problems, and the development speed will be calculated by comparing the same period of one year, one quarter or one month, which is the year-on-year development speed.