... to the design, implementation, analysis and writing of the present paper. The project was designed by GML and THL, the data collection was performed by PHL and YYY, the analysis of the data and ... W. S. Tam, Ben K. K. Li, and Paul T. K. Wong(School of Public Health, The University of Hong Kong) for their role in the development of the survey instrument and for the preparatory work for ... Switzerland [11], 85% in Vietnam [10], 100% inUS [9], and b y 170% in Hong Kong [ 12]. The discre-pancy between the measurements, and the wide rangeof discrepancies, reinforces our concern over the...