There has been a sharp decrease in the number of students who major in natural sciences in their undergraduate years and then take up economics in postgraduate courses. I will attempt to identify the reasons.
First of all, those students who have concentrated on natural sciences very seldom show interest in economics and other social sciences; becoming an economist is no option in their career building. In 1961, when I entered university, the national universities adopted two sets of subjects for applicants at entrance examinations: one for humanities majors and the other for natural sciences majors.
Specifically, humanities majors were required to take only Mathematics I and II, while natural science majors had to take Mathematics I, II and III. The latter no longer had to take Chinese classical literature. Still, each category of students had to take two subjects from the other category.