In a new study from, researchers found that by the end of 2011, 33.7 million Americans will use a tablet at least once a month. This is an increase of 158.6% since 2010, when the iPad was first released. The study estimates a 63.8% increase in users to 54.8 million by 2012. By 2014, that number will shoot up to 89.5 million. A total 35.6% of Internet users will use an iPad at least once per month by the year 2014.

Today, tablets are shared. For example, magazine discovery app Zite released a multiple sign-in option after discovering that 30% of iPad users shared their device with one or more people. According to eMarketer’s data, however, as tablet adoption continues, tablets will move to single-use, much like the smartphones of today.

As the tablet wars continue, the iPad will see more competition from the media consumption-focused Amazon Kindle Fire. Already 22% want a Kindle Fire versus 65% who want an iPad. Then there’s the Barnes & Noble Nook, which is a competitor to the Kindle Fire, does not offer cloud storage and is largely marketed toward women with 2.3 children (it can “fit in a purse or pocket,” so it’s obviously the perfect gift for any woman, right?).

In 2011, 31.5% of tablet users are aged 18-34 and 55.5% are 35 and older. Those numbers will be about the same in 2014, with 18-34-year-olds comprising 34.8% of the tablet market, and ages 35-and-up accounting for 49.3% of total users.

According to a study by Gartner, the iPad is positioned to dominate the tablet market until 2015.