[["", "2007", "2006", "2005"], ["expected dividend yield", "2.13% ( 2.13 % )", "1.79% ( 1.79 % )", "1.62% ( 1.62 % )"], ["risk-free interest rate", "4.60% ( 4.60 % )", "4.59% ( 4.59 % )", "2.84% ( 2.84 % )"], ["expected life in years", "0.25", "0.25", "0.25"], ["expected volatility", "16.26% ( 16.26 % )", "15.92% ( 15.92 % )", "15.46% ( 15.46 % )"], ["weighted average fair value of purchase rights*", "$ 9.80", "$ 10.30", "$ 9.46"]]