I know, it was meant to say the majority of the population USED opiates or cocaine.
Well I don't believe that even that can be construed as a valid statement. And if you read through some of the material on the site I posted you will find that one of the reasons is due to the data, and quality thereof, that is available for the time period. In addition, since most of the population was rural at the time, the use of opiates did not have the same impact on them as it did in the urban areas.
However if you make the statement that many of the people of the time used opiates, I think you would find it easier to support that statement. .