Those figures come from the 20 publishers who reveal their ebook sales numbers to the Association of American Publishers.
Publishers Weekly reports the 81-percent hike marked the first time in 2011 that ebook sales did not double over the same month in 2010.
Overall, for the first 10 months of the year, ebook sales were up 131 percent.
Mass market paperbacks took a hit, with sales falling 37.6 percent.Trade paperback sales were down almost 17 percent, while adult hardcover fell almost 8 percent.
The one high point in print is that religious sales were up more than 12 percent in October.