On the basis of the identity between the Net National Product (NNP) and the Net National Income (NNI) we can suggest two methods of measuring the national income of a country. One may be called the census of production method and the other may be called the census of income method. In the census of production method we make a complete list of all products produced by all the productive units of the country during the year and add them together to obtain the Gross National Product (GNP) total. However, to avoid multiple counting, only the final products or only the values added will have to be taken into account. In the census of income method we make a complete census of all incomes earned by all members of the nation during the year for participation in the production process and add them up to obtain the national income total.