The general price index measures a broader range of Brazilian inflation than the consumer price index. It is constructed from 3 price indices: wholesale price index (60%), consumer price index (30%) and an index of national construction costs (10%). This weighting scheme aims to reproduce the value added of each sector of the economy (wholesale, retail and construction) at the time it was introduced in the 1940s. IGP-M measures the price progression between the 21st day of the previous month and the 20th day of the reference month. IGP-M differs from the other versions because it spans across the last 10 days of the previous period, and only collects data for the first 20 days of the reference period, essentially acting as a mid-month indicator. This measure of inflation is used to correct electric power supply contracts, to index some government-regulated prices and also as a financial market indexing factor.