Garbage. Amsterdam had a murder rate of about 3.6/100,000 in 2007.¹ San Jose, one of the safest cities in the US with a population over 500,000, had a murder rate of 3.5 in 2007². Overall, the murder rate in the US is nearly 4X the Dutch rate.³
¹http://www.expatica.com/nl/articles/news/Record-low-murder-rate-once-again.html
²http://city-data.com
³http:/nationmaster.com
In the Netherlands:
http://www.cbs.nl/en-GB/menu/themas/bevolking/publicaties/artikelen/archief/2005/2005-1666-wm.htm<
Between 1911 and 1930 the number of victims of murder or manslaughter was on average nearly 20 a year. Between 1940 and 1970 it was around 40 a year. It rose subsequently to around 200 a year at the end of the nineties.
Marijuana legalization and lax drug laws were primary reason for increase.