You don't seem to have looked very hard. Click the only chapter available for reading and you'll find on the first page: "the rate of opiate addiction in America increased throughout the nineteenth century, from not more than 0.72 addicts per thousand persons before 1842 to a maximum of 4.59 per thousand in the 1890s; thereafter the rate began a sustained decline."
I didn't think I would have to look in additional links to find something you linked. Why wouldn't I expect you to just supply the end link right from the start?
Click the only chapter available for reading and you'll find on the first page: "the rate of opiate addiction in America increased throughout the nineteenth century, from not more than 0.72 addicts per thousand persons before 1842 to a maximum of 4.59 per thousand in the 1890s; thereafter the rate began a sustained decline."
Letting me know that when you posted the link would have been helpful.