Final answer:
To calculate the percentage change of a variable from one year to another, subtract the start year's value from the end year's value, divide by the start year's value, and multiply by 100. This method assumes the base year value is set at 100.
Step-by-step explanation:
To determine by what percentage a variable has changed from one non-base year to another, you can use the following calculation:
- Determine the value in the starting year and the ending year.
- Calculate the difference between the end value and the start value.
- Divide the calculated difference by the start value to get the rate of change.
- Multiply the result by 100 to convert it to a percentage.
This method assumes that the base year has a value of 100, which is often used in indexes such as the Consumer Price Index, where the year assigned as the base year takes the value of 100. The variables for years before the base year would have values less than 100, and for years after the base year, the values would be more than 100.
For example, if the variable's value was 90 in the start year and 110 in the end year, the calculation would be ((110 - 90) / 90) * 100 = (20 / 90) * 100 ≈ 22.22%. Thus, the variable increased by approximately 22.22% from the chosen start year to the end year.