Table 1.

Characteristics of the study population at wave 9 of YP2007 survey.

Characteristics	N (%)
Education level
High school and below	252 (20.6)
College	400 (32.6)
University	530 (43.2)
Graduate school and above	46 (3.7)
Marital status
Married	618 (50.3)
Single	606 (49.3)
Divorced	4 (0.3)
Average income paid per unit time
<10,000 won	97 (8.1)
10,000 won–less than 20,000 won	816 (67.8)
20,000 won–less than 30,000 won	247 (20.5)
≥30,000 won	44 (3.7)
Refused to answer	24 (2.0)