Respondent selection and interviewing
To be consistent on the invitation of persons to participate in the survey, interviewers approached every fifth adult who passed their way to participate in the survey. As long as the person looked like an adult, this person was approached. If the person was aged over 45 years old, a method described below was applied to determine eligibility for the survey and to discontinue the interview. Once every fifth person was approached, the interviewer must introduce him/her and the purpose of the research and seek their participation.