Table 2. Demographics statistics (n=320)

Survey questionnaires		Respond	Ratio
Gender	Male	165	51.6
	Female	215	48.4
Age	20-29	53	16.6
	30-39	90	28.1
	40-49	67	20.9
	50-59	63	19.7
	60 or more	47	14.7
Education	College	40	12.5
	Bachelor	236	73.8
	MS / Ph.D	44	13.8
Residential area	Seoul	89	27.8
	Metropolitan	131	40.9
	Other Area	100	31.3
Preferred transportation	Car	154	48.1
	Bus	67	20.9
	Subway	99	30.9
Airport access	Car	105	32.8
	Bus	109	34.1
	Subway	106	33.1