Here's what's driven changes in cocaine prices on US streets since the 1980s

Shuttershock/Daniel Loretto

Cocaine has been a high-profile feature of the American drug world since it arrived in the US in the early 1980s.

But since those first few years on the scene, cocaine prices have remained relatively stable, with variations in year-to-year prices in the US likely being driven by foreign affairs as much as by domestic demand.

Precise figures for the movement and sales of illegal drugs are obviously hard to come by.

The cocaine trade, like the drug trade in general, is opaque and run by individuals and groups that are hostile to oversight and inquiry.

Accordingly, analysis of drug prices and how they've change over time involves quite a bit of speculation, but the charts below, documenting the shifts in cocaine prices in the US, grant some insight to how the market has evolved over the last 30 years.