. the company 2019s share repurchase activity in 2012 , 2011 and 2010 was 1 million shares at a cost of $ 92 million , 10.2 million shares at a cost of $ 858 million and 8.1 million shares at a cost of $ 586 million , respectively . no ppg stock was purchased in the last nine months of 2012 during the completion of the separation of its commodity chemicals business and subsequent merger of the subsidiary holding the ppg commodity chemicals business with a subsidiary of georgia gulf