Table 1.

Demographic characteristics of the respondents.

Variables		Frequency	Percentage
Sex	Male	304	51.3
	Female	289	48.7
Age	20–29 years	132	22.3
	30–39 years	139	23.4
	40–49 years	169	28.5
	50–59 years	153	25.8
Marital status	Singlea	263	44.4
	Couplea	330	55.6
Occupation	Office worker, etc.b	423	71.3
	Student	82	13.8
	Housewife, unemployed and other	88	14.8
Monthly income	Under $1,792.11	47	7.9
	$1,792.11–$3,584.23	179	30.2
	$3,584.23–$5,376.34	219	36.9
	Over $5,376.34	148	25.0
Residential area	Capital area (including Seoul)	394	66.4
	Non-capital area	199	33.6
Device type	Android	480	80.9
	Apple iOS	113	19.1
Group	Low-risk group for smartphone addiction	491	82.8
	High-risk group for smartphone addiction	102	17.2
Total		593	100.0

^aSingle: never married, divorced, separated, or widowed; Couple: married or living with a partner.

^bOffice worker, etc.: office worker, administrative position, service industry position, professional technician, freelancer, and production employee. The exchange rate for Korean won to the US dollar is 1,116.00 won (buy and sell base rate in January 31, 2019).