The impact of gross domestic product

Plotting publications vs population reveals an interesting trend. There seems to be two distinct groups of countries: one with a steep linear correlation between population size and scientific output (e.g. USA, Japan, UK, Italy, France), and one with a much more shallow linear correlation (e.g. India, Brazil, Russia, Mexico). Since the size of the symbols is proportional to the country's GDP, it appears that the first group of countries is relatively richer, which in-turn suggests an advantage in research resources. An interesting outlier seems to be China, which seemingly is in transition between the two groups and not yet ready to take a lead in the publications ranking.