过去150年中，发达经济体平均每年增长3 % ， 而一些发展中国家在20年甚至更长的时间里保持7%甚至更高的年增长率。
Over the last 150 years, developed economies have grown at an average rate of 3% per year, whereas some developing countries have achieved annual growth rates of 7% or higher for periods of 20 years or longer.