All it took was 60 million people and the sewage from a selection of countries studied over a period of six years, and we have the answer to a question that not many of us were actually asking.

Which drugs are the most popular in the world?

I’m guessing Cape Town would go with cocaine.

Scientists screened the sewage for cocaine, amphetamines, and MDMA to build a comprehensive wastewater map of illicit drug use in more than 37 countries around the world.

Here’s VICE with a breakdown of their findings:

According to the study, which was published Wednesday in the journal Addiction, cocaine use is on the rise across Europe, methamphetamine is most prevalent in North America and Australasia, and the Netherlands had the highest rate of MDMA use.

Okay, we know the Brits love cocaine – a little too much, by the look of things.

“This is the largest wastewater‐based epidemiology study ever performed in terms of cities (120) and countries (37) involved and of the monitoring duration (2011–17),” said the team, which was co-led by Iria González-Mariño, an assistant professor of chemistry at the University of Salamanca in Spain.

Six years is a long time to study poop, but somebody has to do it. In fact, sampling wastewater for residue from drugs has become an increasingly popular method to track patterns of drug use and distribution in the drug market.

The results showed that overall drug use was most prevalent cities such as Antwerp, Amsterdam, Zurich, London, and Barcelona, while cities in Greece, Portugal, Finland, Poland, and Sweden had the lowest rates of drug residue in wastewater.

Cocaine was most popular in London, Bristol, Amsterdam, Zurich, Geneva, St Gallen, and Antwerp. Amphetamine seemed to be on the rise in Barcelona, Geneva, Berne, Zurich, Dortmund, and Berlin, but methamphetamine use was far lower in Europe than in the United States and Australia.

While the Netherlands had the highest rates of MDMA use, the drug was also popular in Helsinki, Oslo, Brussels, Dortmund, Zagreb, Zurich, Geneva, and Barcelona.

A study conducted earlier this year in Cape Town uncovered abnormally high levels of sewage and pharmaceuticals in our oceans.

They didn’t break down the drugs, but I reckon they’d find a fair amount if they did.

[source:vice]