Of the participants. In 2007 , the average monthly income of the Korean family was $3,220 . However approximately half of the participants (50.6%) did not know their monthly family income. Most of the participants (87.8%) lived with both their mother and father ,9.3% lived with a single parent , and 0.1 % lived with neither parent Approximately half of thir fathers (51.3%) And 38.3% of their mothers had completed at least college ed education . Among the participants, 4.7% had the experience of smoking , and 8.9%had the experience of drinking alcohol.