Gross national income (GNI) is a measure of income produced by a nation.It is closely related to the gross domestic product (GDP), and includes many of the same figures.Economic organizations regularly produce rankings of nations by GNI, with various adjustments to contextualize the numbers they present, and this information is often available to the public.t is closely related to the gross domestic product (GDP), and includes many of the same figures. Economic organizations regularly produce rankings of nations by GNI, with various adjustments to contextualize the numbers they present, and this information is often available to the public.