Seoul, Oct 25 : The number of South Koreans who moved to different residences in the country sank to a 50-year low in September on population aging and the sagging real estate market, the statistics agency said on Wednesday. Around 450,000 people changed their residences last month, down 1.6 per cent from a year earlier, according to the data compiled by Statistics Korea. It marked the lowest monthly tally for any September since 1973 when the figure came to 378,000. The government began compiling the related data since January 1970, reports Yonhap News Agency. The population mobility rate -- the percentage of those relocating per 100 people -- came to 10.7 per cent last month, down 0.2 percentage point from the previous year, the data showed. The decline came as the number of people in their 20s who changed their residences logged an on-year fall last month. People in their 20s and 30s tend to frequently change their residences due to housing expenses and work. But the number of such young adults has fallen amid low birthrates, while that of senior citizens rose due to rapid population aging. The decline also came as housing transactions remained in the doldrums over rising interest rates and an economic slowdown. Seoul chalked up a net outflow of 1,370 people last month on high home prices, and Gyeonggi province, which surrounds the capital, and the western port city of Incheon posted net inflows of 1,238 and 2,917, respectively, the data showed. The second-largest city of Busan, 320 km southeast of Seoul, saw a net outflow of 961 people, and North Gyeongsang Province experienced a net outflow of 661 residents, the data showed. During the third quarter of 2023, the number of people who changed their residences climbed 2.4 per cent on-year to come to 1.47 million, marking the first quarterly increase since the fourth quarter of 2020. The mobility rate rose 0.3 percentage point to 11.4 per cent in the third quarter, the data showed. /IANS