5. Routes of ingestion - Notes

Subtitle

• Quality of cocaine will be discussed in chapter 11.
• In the following subtables we will include the proportions of missing values. The sometimes high values for `missing' are probably caused by interviewer error. Instead of using the category 'don't know' some interviewers omitted to fill in a code. Because we cannot be sure if this omission really represents a 'don't know' we give the known proportions of 'don't know' plus the missing values.