U.S. tablet sales to soar as sharing of devices decreases

Tablets still tend to be early adopter devices, but they’re quickly becoming mainstream tools. By the end of 2014, one in every three Americans or 90 million users is expected to have a tablet, according to a new estimate by eMarketer.

The research firm said Monday that by the end of 2011, 33.7 million Americans will use a tablet device, up 158.6 percent over last year. Tablets sales are expected to grow 62.8 percent to 54.8 million next year, and will grow to 75.6 million units in 2013 and 89.5 million by 2014.

Over time, eMarketer said tablet sales will be driven by people buying their own tablets instead of sharing devices, which is what happens a lot now. Just like computers went from being more family-owned devices to ultimately very personal machines, tablets will become more like smartphones, tied to one user rather than passed between people. The iPad (s aapl)will continue to be the leading device in the tablet market, though its dominance will wane with the arrival of more competition like the Kindle Fire (s amzn) and the Nook Tablet (s bks). Its current penetration in the tablet market will slip from 83 percent to 68 percent by 2014.

That’s still impressive considering how much work has gone into knocking off the iPad. We’ll have to see if the iPad’s loosening grip on the market accelerates with a proliferation of a lot of cheaper alternatives, or if Apple responds by competing even more on price. But with a big iPad 3 update coming next year, Apple should continue to roll, and is in fact expected to sell more iPads than HP (s hpq) will sell PCs in the first half of 2012.

The demographics of tablet users are also shifting over time. Though women make up less than half of tablet users, the gender gap is expected to close eventually. We’ve noted before that women seem more attracted right now to e-readers while men prefer tablets. As some of the distinctions between the two devices blur, we should also see tablets garner similar appeal across both genders.

EMarketer, which builds its forecast of tablet users on an analysis of survey data and other research, expects that while 55.5 percent of current tablet users are 35 or older, that figure will slip to 49.3 percent by 2014. Meanwhile, 18- to 34-year-olds tablet users will rise from 31.5 percent to 34.8 percent of tablet users by 2014. I’ll be interested to see if tablets can be popular learning tools for students and children, which could help the market explode.