This is the 3422nd most frequent Korean word.
대한민국이
"대한민국이" means "South Korea" (subject form).
In this sentence, '대한민국이' acts as the subject, emphasizing South Korea as the entity undergoing economic growth.
대한민국이 경제적으로 성장하고 있습니다.
South Korea is economically growing.
Here, '대한민국이' is again the subject, referring to the nation and its collective duty.
대한민국이 책임을 다해야 합니다.
South Korea must fulfill its responsibilities.
In this case, '대한민국이' introduces the subject of the thought, expressing an opinion about the country.