http://www.briancbennett.com/charts/fed-data/crime/intox-arrests.htmhttp://www.briancbennett.com/charts/fed-data/crime/intox-arrests.htm
You need to break that up into two pieces.
From 1980 to 1990, combined heroin/cocaine arrests, according to your charts, increased rapidly from 70K to 600K. During that same period, heroin use was flat but cocaine use dropped 65%.
Since 1990, arrests have been flat and cocaine/heroin use has also been flat.
All of these statistics are from your source. Where did you get this 30% heroin increase -- the source you cited said heroin use has been flat for over 10 years at about .1%. Did it jump from .1% to .13% without us noticing?
"BTW, notice that while arrests and demand for heroin have increased from 1979-2004, the price has dropped and the purity increased"
Again, according to your source, arrests and demand for heroin have been flat since 1990. Purity has been flat since 1990, but the price has dropped. Well, with little demand, that's what happens in a free market.