It looks like all those avowed Kindle fanatics might be going through ink withdrawal -- or so says a new report funded by a few titans of old media.

The report, published last week by the Book Industry Study Group (BISG), found that fewer consumers are purchasing books exclusively in electronic formats, while the number of booklovers who have "no preference" for e-books over print books is increasing.

According to the BISG, the percentage of e-book consumers who purchased books "exclusively or mostly" in e-book formats has decreased from 70 percent in August 2011 to 60 percent in May 2012. Meanwhile, the number of respondents who have no preference for either e-book or print formats, or who buy some genres in e-book format and others in print, rose from 25 percent to 34 percent.

The study suggests that the widespread fervor over e-books, which had been growing steadily since Amazon (Nasdaq: AMZN) first released its Kindle e-reader in 2007, might be leveling off. While the results of the survey might also appear to be a dream come true for the traditional publishing industry, it's worth mentioning that the research was funded by Barnes & Noble (NYSE: BKS), the world's largest bookstore chain, and Baker & Taylor, one of the world's largest book distributors.

However, BISG said in a statement that the survey itself was conducted independently by Bowker Market Research, a New Jersey-based research company, and to be sure, the results are not all good news for the ink-and-paper set. In addition to consumers' growing willingness to purchase books across multiple platforms, the study also found that more people are using tablet computers as e-readers -- a trend that could point to consumers becoming more comfortable with backlit screens as opposed to e-ink.

In another sign that Amazon's dominance knows no bounds, the report also found that the Kindle Fire has overtaken Apple's (Nasdaq: AAPL) iPad as the e-reader of choice among e-book consumers. Ownership of the Kindle Fire has grown from 7 percent of respondents in December 2011 to 20 percent just six months later, while ownership of Apple's iPad has remained static at 17 percent. Between those two companies, though, the market doesn't seem to have much room for additional players -- a mere 5 percent of respondents reported owning Barnes & Noble's NOOK.

In a statement, BISG's deputy executive director, Angela Bole, said device ownership is an important factor in predicting future habits. "In previous studies, changes in levels of device ownership have presaged changes in e-book buying behavior," she said. "One of the strengths of this study is that it can plot such evolution, preparing publishers for what e-book consumers want and expect from them next."

BISG first began publishing the report -- dubbed "Consumer Attitudes Toward E-Book Reading" -- in 2009. The latest addition is the third installment. The study tracks the habits and preferences of print book consumers who say they have acquired an e-book or a dedicated e-reading device within the past 18 months. The data is derived from a nationally representative panel of book consumers that includes men, women and teens. Researchers begin with a wide net -- some 65,000 consumers -- and from there they choose 1,000 consumers who indicated that they had either purchased a digital book or e-book or that they owned a dedicated e-reader device, such as Kindle, NOOK or Sony Reader.

Despite those meticulous methods, however, the researchers' results do not completely jive with other industry surveys published by BISG. The organization's "BookStats 2012" report published in July found that e-books are still on the rise -- making up 15 percent of all trade book sales in 2011, up 5 percent from the previous year. That same report also found that total book sales decreased slightly, with total revenues from book publishers clocking in at $27.2 billion in 2011, compared to $27.9 billion in 2010.

While brick-and-mortar bookstores still account for the largest percentage of books sold, that number is also dropping. In 2011, physical bookstores accounted for 31.5 percent of publishers' total net dollar sales, down 12.6 percent from 2010. So even if booklovers are showing signs of ink withdrawal, it might only be a temporary relapse.