Accounts showing the main aggregates relating to national income and its components; these include gross domestic product, gross national product, national income after deducting capital consumption, and components including consumption, net investment and gross investment, government expenditure, exports, and imports. National income accounts frequently also include data on stocks as well as flows: that is, the domestic stock of productive capital, and external assets and liabilities. National income accounts normally include information on changes in price levels, and show the various aggregates at both current and constant prices, that is, in both nominal and real terms. Data usually refer to whole years; where they are provided for shorter periods, they may or may not be seasonally adjusted.