Gross domestic product (GDP) is the sum of domestically produced goods and services expressed in prices. It is a major indicator reflecting the state of the national economy. GDP is calculated in the following way: GDP = C + I + S + E - M, where C — consumption, I — investment, S — state government expenditures, E — export, M — import. GDP is expressed as an index relative to the previous period, and as an absolute value of the sum of prices for manufactured goods and services. Despite the importance of the indicator, its impact on the market is decreasing, because its value is usually predicted by the market based on other data, and also due to repeated revisions of the value of GDP after its first release.