Nintendo's annual income. GDP is figured on a national level. What percentage of the market share does Nintendo have? How much do video games and consoles generate per year? What percentage of the US GDP is accounted for by video gaming?
You need to know:
US GDP
$ amount video game sales annually, which will allow you to figure what percentage of the GDP it is
% video game market share Nintendo has, which will allow you to figure what percentage of the GDP Nintendo contributes.