Economic and demographic changes will always impact crime rates and of course, these factors would have played their part in the noticeable improvement in New York. However, zero tolerance has proved successful in many instances and provides a more stable promise of crime reduction less susceptible to transient factors (such as economic and demographic ones).  For example, the Swedish parliament introduced its ‘drug-free society’ as the official goal for the drug policy in 1978. Long before such policies were called ‘zero tolerance. The Attorney General in 1980 stopped allowing for waivers for possession of drugs for personal use. Meanwhile, police were to prioritize the crack down on those in possession of drugs. In 1988 all non-medicinally prescribed usage became illegal. Finally, in 1993 the police were permitted to take blood or urine samples from suspects. [1]  This zero tolerance approach is now cited by the UN as one the main reason for Sweden's relatively low drug prevalence rates. [2]  [1] Wikipedia, ‘Zero Tolerance’,  , accessed 21 September 2011  [2] United Nations Office on Drugs and Crime, Sweden’s Successful Drug Policy: A Review of the Evidence, February 2007,  , accessed 21 September 2011