《世界统计年鉴》中有许多关于Real GDP的测量指标，例如，
Real Gross Domestic Product per Capita Relative to the United States (G-K method, current price)
Real Gross Domestic Product per Capita Relative to the United States (EKS method, current price)
Real Gross Domestic Product per Capita Relative to the United States (weighted CPD method, current price)
Real GDP per capita (Constant Prices: Laspeyres), derived from growth rates of c, g, i
Real GDP per capita (Constant Prices: Laspeyres), derived from growth rates of domestic absorption
Real GDP per capita (Constant Prices: Chain series)
Real GDP Chain per equivalent adult
Real GDP Chain per worker
Real GDP Laspeyres2 per worker
Real GDP Laspeyres2 person engaged
Real GDP Laspeyres2 per person counted in total employment
Real GDP Laspeyres2 per hour worked by employees
有这么多Real GDP，做经济增长研究时，我们到底用哪个呢？