European GDP growth 2012. Is economic growth in Europe related to growth in the United States? Here’s a scatterplot of the average growth in 25 European countries (in % of Gross Domestic Product) vs....

European GDP growth 2012. Is economic growth in Europe related to growth in the United States? Here’s a scatterplot of the average growth in 25 European countries (in % of Gross Domestic Product) vs. the growth in the United States. Each point represents one of the years from 1970 to 2011.

Explain the meaning of R²
in this context.