-(으)ㄴ 지 indicates how much time has passed since some situation or action occurred and thus corresponds to 'since' in English.

It can be expressed in various ways, including -(으)ㄴ 지 ~ 되다, -(으)ㄴ 지 ~ 넘다 and -(으)ㄴ 지 ~ 안 되다.

When the verb stem ends in a vowel or ㄹ, -ㄴ 지 is used, and when it ends in a consonant, -은 지 is used.

Kimchi Reader

Indicates how much time has passed since some situation or action occurred