The income data of the other 20 countries are used to demonstrate the performance of Paul and Shankar [3]’s functional form and those of the other popular functional forms based on IIM.

The income data of the other 20 countries are used to demonstrate the performance of Paul and Shankar [3]’s functional form and those of the other popular functional forms based on IIM.采用其余20个国家的收入数据，用以验证Paul与Shankar[3]提出的函数形式，以及其他基于IIM的主流函数形式的性能表现。