Internet search results might not be the best way to determine the amount of drugs that are being used, but they do provide insight into the relationship between drugs and culture.
The folks over at Withdrawal.net, a site that lists substance abuse recovery resources, have made an animated map that shows what types of illegal drugs people are searching for online. The map gives an interesting look into the shifting drug culture of the United States. For instance, searches for drugs like meth and various prescription drugs have increased rapidly over the past decade. Meth use has steadily been declining since around 2005 yet the map shows that at around 2005 searches for meth started increasing. Then in about 2008, they drop way down, not picking up again until 2012 (Breaking Bad influence?).