Our objective is to "explain" per capita GDPs by the countries' latitude, using PPP-based data for 138 countries in 1985 (PPP = purchasing power parity). A simple approach is formulated which nevertheless accounts for as much as two-thirds of the variance of the per capita GDPs.

Purchasing power parity-based data for gross domestic products are used to assess the affluence of the G-7 countries in the period 1885-1994. A simple Cobb-Douglas model is developed for the eligibility to this Group of Seven.