This is the 11572nd most frequent Korean word.
나온지
"나온지" means "since (something/someone) came out."
Here, '나온지' is employed to inquire about the duration since the new album's release.
새 앨범이 나온지 얼마나 됐나요?
How long has it been since the new album came out?
The word '나온지' is used to refer to the amount of time that has passed since an event, specifically the release of the movie.
그 영화가 나온지 벌써 1년이 됐어요.
It has already been a year since that movie came out.
In this sentence, '나온지' represents the elapsed time since the book was published, emphasizing its age.