From a 2 b

GDP 2 NDP 2 NI 2 PI 2 DI

http://en.wikipedia.org/wiki/GDP
http://en.wikipedia.org/wiki/Net_Domestic_Product
http://en.wikipedia.org/wiki/National_income
http://en.wikipedia.org/wiki/Total_personal_income
http://en.wikipedia.org/wiki/Disposable_income