Lenovo expanded significantly in 2005 through its acquisition of IBM’s personal computer business, including its ThinkPad and ThinkCentre lines. As of January 2013, shipments of THINK-branded computers have doubled since Lenovo’s takeover of the brand, with profit margins thought to be above 5% .[79] Lenovo aggressively expanded the THINK brand away from traditional laptop computers in favor of tablets and hybrid devices such as the ThinkPad Tablet 2, ThinkPad Yoga, ThinkPad 8, ThinkPad Helix, and ThinkPad Twist; the shift came as a response to the growing popularity of mobile devices, and the release of Windows 8 in October 2012. Lenovo has achieved significant success with this high-value strategy and it now controls more than 40% of the market for Windows computers priced above $900 in the United States.[80]