In 1998 the percentage of 15- and 16-year-olds in Iceland who had been drunk in the previous month stood at 42 percent. Today it is 5 percent. The percentage who have ever used cannabis was 17 percent; today it is 7 percent. And the percentage of those smoking cigarettes every day fell from 23 to 3. What does Iceland know that the rest of the world doesn’t? The answer is simple: Today the Iceland teens are doing other things: Skating, swimming, dancing…