Once you have calculated GNI/GNP, what would need to be done to calculate the average wealth per citizen?

Divide by the Population.

Explanation:

In calculating the average wealth per citizen, the PER CAPITA method is used. That means that the measure that was used to calculate national income be it GDP, GNP or GNI is divided by the total number of the population to see how much is theoretically due to each person in the country.

For example, if the GNI is $10,000,000 and the population of the country is 10,000 then the Average wealth or GNI per capita is,

= 10,000,000/10,000

= $1,000