Underlying inflation measures the more lasting inflation rate, or inflation trend, as the effects of prices that fluctuate substantially are given less weight in these measures. And they can be calculated in different ways. Here there are two different measures of underlying inflation that the Riksbank produces. One is called Trim85 and the other Und24. The calculation of both measures is based on the CPI divided into 70 sub-groups and calculated as annual percentage changes in the CPI.
In the Trim85 measure, 7.5 per cent of the highest and lowest price change rates for the sub-groups included in the CPI are removed each month. Thus, 85 per cent of the total weighting in the CPI remains in this measure. All of the sub-groups are retained in Und24 but are given different weights than in the CPI. Goods and services that vary substantially in prices are given a lower weight and vice versa.
The two underlying measures of inflation are published every month, on the same day as new outcomes for the CPI are published by Statistics Sweden.