[["", "2009", "2008", "2007"], ["expected volatility", "28.7% ( 28.7 % )", "27.3% ( 27.3 % )", "23.5% ( 23.5 % )"], ["risk-free interest rate", "1.4% ( 1.4 % )", "1.7% ( 1.7 % )", "4.8% ( 4.8 % )"], ["dividend yield", "3.1% ( 3.1 % )", "2.9% ( 2.9 % )", "1.5% ( 1.5 % )"], ["expected life ( in years )", "4.2", "4.2", "4.0"], ["contractual life ( in years )", "7", "7", "7"], ["expected forfeiture rate", "3.0% ( 3.0 % )", "3.0% ( 3.0 % )", "5.0% ( 5.0 % )"]]