This study describes behavioral characteristics of Korean population over twenty years old in a variety of activities of daily living by analyzing the raw data of the time use survey provided by Statistics Korea (KOSTAT). Seven activities and forty four sub-activities of daily living were selected for analysis : personal care, employment, household care, family care, voluntary work and community participation, social life, recreation and leisure, and travel. In order to quantitatively understand how Korean adults spend their time for a day and how their lifestyle changes over time, we collected the time recorded by 3,673 respondents in three surveys over the past ten years (in 1999, 2004, and 2009). Then, we performed analysis of variance to compare the behavioral characteristics by user age and gender based on the mean time of each activity. The differences in behavior among user groups and over time could be used to design ergonomic products and services based on user experience, especially for universal design of housing and transportation facilities.