[DiogenesLamp]

These guys were civilians in 1880 and had dispersed around the country. How did they get such an accurate civilian count in 1880, but not in 1900?

War records. Look it up. I'm pretty sure Confederate soldiers stayed in the South, and i'm pretty sure Wounded Union soldiers likewise stayed in the North, and very likely neither group moved around a lot.

Read up on "Soldier's Disease."

The Civil war is what started narcotic addiction in this country. Prior to that, few people knew of, or had access to, large quantities of narcotics.

[Ken H]

Your link says nothing about how the data was collected for 1880 and 1900, nor why data on civilians in 1880 would be more accurate than data on civilians in 1900.

Most telling of all, the people in charge of the Drug War put forth those figures without your caveats, which would have been beneficial to their argument. What we have is a situation similar to an expert witness for the prosecution giving testimony that favors the defense.

Your star witness hosed your case.