In December 2013, the combined market share of Windows 8 and 8.1 reached the ten percent mark, 15 months after the operating system was released. In comparison, Windows 7 reached the same level after a mere six months.
Follow up:According to data from Net Applications, an acceleration of Windows 8’s market share is not on the cards for early 2014. In January, it increased by just 0.09 percent.
You will find more statistics at Statista