CSO publication, , 11am
The formula used to calculate the percentage change between any two periods is as follows:
| Percentage Change | = | ( | IndexCP-IndexPP | ) | x | 100 |
| IndexPP |
where IndexCP is the index for the current period and IndexPP is the index for the previous period in the same base reference period.
Note: the percentage changes are published rounded to 1 decimal place.
Example 1: In May 2023, the 12 months percentage change between May 2023 and May 2022 (Base: December 2016=100) was calculated as follows:
| Percentage Change | = | ( | 119.0-111.6 | ) | x | 100 | = | 6.6% |
| 111.6 |
Example 2: In May 2023, the 1 month percentage change between May 2023 and April 2023 (Base: December 2016=100) was calculated as follows:
| Percentage Change | = | ( | 119.0-118.6 | ) | x | 100 | = | 0.5% |
| 118.6 |
In December 2023 (i) the annual percentage change (i.e. annual rate of inflation) for December 2023 and (ii) the annual average percentage change (i.e. annual average rate of inflation) for 2023 were published in the Consumer Price Index release.
| Percentage Change | = | ( | IndexCP-IndexPP | ) | x | 100 |
| IndexPP |
where IndexCP is the index for the current period December 2023 and IndexPP is the index for the previous period December 2022 in the same base reference period.
| Percentage Change | = | ( | 121.1-115.8 | ) | x | 100 | = | 4.6% |
| 115.8 |
i.e annual rate of inflation = 4.6%
(ii) the annual average percentage change (i.e. annual average rate of inflation) for 2023 was calculated in two steps as follows:
Step 1: The annual average CPI for the current and previous years was calculated using the following formula:
| Annual Average CPI | = | ( | Σ | 12 | CPI | ) | x | 100 | = | 0.5% |
| t=1 | ||||||||||
| 12 | ||||||||||
where CPI is the CPI (All items) from t=1 to 12 (i.e. January to December) and ∑ represents summation of the monthly CPI (All Items).
i.e. the annual average CPI for 2023 is
| Annual Average CPI | = | ( | 114.9 + ...+121.1 | ) | = | 119.4 |
| 12 |
Step 2: The annual average percentage change for 2023 was calculated using the following formula:
| Percentage Change | = | ( | IndexCP - IndexPP | ) | x | 100 |
| IndexPP |
where IndexCP is the index for the current period and IndexPP is the index for the previous period in the same base reference period (i.e. Base December 2016 = 100).
| Percentage Change | = | ( | 119.4-112.3 | ) | x | 100 | = | 6.3% |
| 112.3 |
The Central Statistics Office (CSO) neither encourages nor discourages the use of price adjustment measures in contractual agreements. The decision to employ an indexation mechanism, as well as the choice of the most suitable index, is up to the individual or party.
The CSO cannot provide assistance in relation to legal questions. The CSO can only provide basic assistance on statistical questions. However, this assistance is provided without acceptance of any responsibility by the CSO.