Seung jun Park Daegu University   201 Daegudae-ro, Jillyang-eup 201 Daegudae-ro, Jillyang-eup Gyeongsan, Gyeongsangbuk-do 38453 South Korea   sjpark-econ@daegu.ac.kr   https://econ.daegu.ac.kr           JEL Areas: O4 : Economic Growth and Aggregate Productivity: General J1 : Demographic Economics: General