Trimmed-Mean CPI is a measure of core inflation that excludes CPI components whose rates of change in a given month are located in the tails of the distribution of price changes. This measure is based on 55 components in the CPI basket. The series of the components adjusted to remove the effect of changes in indirect taxes, are seasonally adjusted. This measure helps filter out extreme price movements that might be caused by factors specific to certain components. In particular, CPI-trim excludes 20 per cent of the weighted monthly price variations at both the bottom and top of the distribution of price changes, and thus it always removes 40 per cent of the total CPI basket. These excluded components can change from month to month, depending on which are extreme at a given time.