total market value of the final goods and services produced by a nation's economy during a specific period of time (usually a year), computed before allowance is made for the depreciation or consumption of capital used in the process of production. It is distinguished from net national product, which is computed after such an allowance is made. The GNP is nearly identical to gross domestic product (GDP) except that the latter does not include the income accruing to a nation's residents from investments abroad (minus the income earned in the domestic economy accruing to nonnationals from abroad). Gross national product is a convenient indicator of the level of a nation's economic activity. In 1991 the United States substituted GDP for GNP as its main measure of economic output.