Apple Inc. will continue to retain the lion's share of the tablet market as its new 4G-enabled iPad readies for competition from Windows 8-based products, and a cheaper iPad 2 takes on Amazon's popular Kindle Fire, analysts said. Shares of Apple inched up a percent to as much as $535.89 in morning trade on Thursday, after the company unveiled an upgraded version of its popular iPad tablet, featuring a more powerful chip, high-definition screen, sharper camera and access to new high-speed wireless networks. Credit Suisse said Apple will command 66 percent share of the tablet market in 2012.