Table 1:

General characteristics of the subjects (N=1,541)

Category		n (%) or mean±S.D.
Sex	Male	555 (36.0)
	Female	986 (64.0)
Age	29 or less	263 (17.1)
	30∼39-year-old	490 (31.8)
	40∼49-year-old	500 (32.4)
	50 or higher	288 (18.7)
	mean±S.D	39.9±9.71
Position	Staff	1,384 (89.8)
	Manager	157 (10.2)
Educational level	Middle school graduate or less	9 (0.6)
	High school graduate	686 (44.5)
	University graduate	816 (53.0)
	Graduation school or higher	30 (1.9)
Working years	Less than 1 year	52 (3.4)
	1∼5 yr	487 (31.6)
	5∼10 yr	385 (25.0)
	10∼15 yr	287 (18.6)
	15∼20 yr	199 (12.9)
	20 yr or more	131 (8.5)
	mean±S.D	9.1±6.73
Monthly average wage	Less than 2 million Korean Won	229 (14.9)
	2∼3 million Korean Won	785 (50.9)
	3∼4 million Korean Won	414 (26.9)
	4 million Korean Won or more	113 (7.3)
	mean±S.D	262.2±82.48
Weekly average working hours	Less than 40 h	69 (4.5)
	40 h	558 (36.2)
	41∼52 h	736 (47.8)
	53 h or more	178 (11.6)
	mean±S.D	45.6±7.91