Tablet sales are expected to surge this year, with Apple’s iPad still ruling the market, says a report from researcher Gartner.

The company forecasts 2011 global tablet sales to reach 63.6 million units, a 264% jump compared to last year.

Apple’s grip on the market remains tight, as the iPad is expected to account for 73% of the tablets sold this year.

“Apple delivers a superior and unified user experience across its hardware, software and services. Unless competitors can respond with a similar approach, challenges to Apple’s position will be minimal,” says Carolina Milanesi, research vice president at Gartner, in a statement.

Tablets running on Google’s Android operating system are predicted to represent 17% of sales, a 3% bump from 2010.

However, Android is forecast to cut into the iPad’s market share over the next few years. Tablet sales will hit 326.3 million units by 2015, Gartner says, with 45% of those credited to the iPad.