Consumer Price Index - Calculating Index Changes
| Movements of the indexes from one period to another are usually expressed as percent changes rather than changes in index points because index point changes are affected by the level of the index in relation to its base period while percent changes are not. This example illustrates the computation of index points and percent changes. | ||
| Step 1: | ||
| Calculating the index point change: | ||
|
CPI- Anchorage 2012 Less CPI for previous period- Anchorage 2011 |
205.916 -201.427 |
|
| Equals index point change | 4.489 | |
| Step 2: | ||
| Calculating the percent change: | ||
| Index point difference Divided by the previous index (Anchorage 2011) | 4.489 / 201.427 = 0.0222859 |
|
| Results multiplied by 100 Percent change (Anchorage CPI 2012) |
0.022285 * 100 = 2.22859 2.2 (rounded 2.22859) |
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