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Note 14. Stock-Based Compensation (Detail) - Estimated Fair Value for the Employee Stock Purchase plan	3 Months Ended
	Nov. 30, 2011	Nov. 30, 2010
Dividend yield	1.11%	1.25%
Employee Stock Purchase Plan Fair Value Determinations [Member]
Risk-free interest rate	0.02%	0.14%
Expected volatility	18.00%	10.00%
Dividend yield	1.25%	1.20%

The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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