GNP also measures the output generated by a country's businesses located domestically or abroad. It can be defined as a piece of economic statistic that comprises Gross Domestic Product (GDP), and income earned by the residents from investments made overseas. Simply put, GNP is a superset of the GDP.Per capita income or average income measures the average income earned per person in a given area in a specified year. It is calculated by dividing the area's total income by its total population. GNP also measures the output generated by a country's businesses located domestically or abroad. It can be defined as a piece of economic statistic that comprises Gross Domestic Product (GDP), and income earned by the residents from investments made overseas. Simply put, GNP is a superset of the GDP.