The national income of a country can be estimated by the

The national income of a country can be estimated by the "expenditure method". The expenditure method measures the total amount of spending in the economy by households, businesses, governments, and foreigners. This includes consumption expenditures, investment expenditures, government purchases, and net exports. By summing up all these expenditures, economists can estimate the total output and income of a country over a given period of time. Thus, the expenditure method is one of the most commonly used methods for estimating the national income of a country.