[["", "2014", "2013", "2012"], ["expected volatility", "21.7% ( 21.7 % )", "22.1% ( 22.1 % )", "24.0% ( 24.0 % )"], ["risk-free interest rate", "1.6% ( 1.6 % )", "0.9% ( 0.9 % )", "0.8% ( 0.8 % )"], ["dividend yield", "2.5% ( 2.5 % )", "2.4% ( 2.4 % )", "2.2% ( 2.2 % )"], ["expected life ( years )", "5.2", "5.9", "6.1"]]