The country's total population surpassed 50 million for the first time last year, however, the number of young people is decreasing notably, according to the Statistics Korea 2015 Census released, Wednesday.
The census, which is conducted every five years, showed that the total population stood at 51.07 million as of November 2015. That is a 1.36 million, or 2.7 percent, increase from the last count in 2010.
On average 509 people live on one square kilometer of land here; but in Seoul, the figure soars to 16,364. Almost 49.5 percent of Koreans live in the Seoul metropolitan area, Incheon and Gyeonggi Province. The capital is home to 19.4 percent of Koreans, while 24.4 percent live in Gyeonggi Province. The southern port city of Busan has 6.8 percent of the population, while South Gyeongsang Province has 6.5 percent.
While the total population has increased, Korea is aging rapidly. The number of babies and children, aged 14 or younger, decreased by 5.18 million from 1985 to 6.91 million in 2015, while the number of senior citizens, aged 65 or older, increased by 4.82 million to 6.57 million during the same period.
As a result, senior citizens make up 13.2 percent of the population, compared to 2010 when they constituted 11 percent.
The working age population, aged between 15 and 64, made up 72.8 percent of the total population, but analysts expect this to start to decrease from 2018.
The median age of Koreans is 41.2, up three years from 2010. This is higher than the 27.3 in India, 36.8 in China and 37.8 in the United States; but lower than 46.5 in Japan and Germany, and 43.4 in the United Kingdom.
The most common surname here is Kim, accounting for 21.5 percent of all Koreans, followed by Lee with 14.7 percent, Park with 8.4 percent and Choi with 4.7 percent.
Foreigners made up 2.7 percent of the total population at 1.36 million people. More than half of them are of Chinese nationality, including Korean Chinese; followed by Vietnamese at 9.3 percent, Thais at 5.7 percent, Americans at 4 percent, and Filipinos at 3.8 percent.
On average, Korean households have 2.53 members. While typical Korean households between 1990 and 2005 had four members, now one-person households are the most common, making up 27.2 percent of the total. In 1990, the ratio stood at a mere 9 percent.
There are 300,000 multicultural households in the country, 1.6 percent of the total.
The statistics also showed Koreans' love for apartments. Nearly half of households, or 48.1 percent, live in apartments, up 1.9 percent from 2010. The ratio of apartments is especially high in Gwangju and Sejong, where over 62 percent of households reside in them.