National income is the total monetary value of all goods and services produced by a nation during a period of time. It is the sum of all factor income generated during a production year and serves as an indicator of a nation's economic activity. The total amount of income accruing to a country from economic activity in a year is known as national income. GDP, which equals private consumption plus gross private investment plus government investment plus government spending plus exports minus imports, provides an economic snapshot of a country and its growth rate. GDP can be calculated in three ways using expenditures, production, or incomes.