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DESCRIPTION OF THE BUSINESS, BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)
 12 Months Ended
May 31, 2012
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block] Schedule Of Share Based Payment Award Stock Options Valuation Assumptions

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2012

 

 

2011

 

 

2010

 

Estimated fair value of stock options granted

 

$

9.30

 

$

8.15

 

$

8.34

 

Assumptions:

 

 

 

 

 

 

 

 

 

 

Expected dividend yield

 

 

1.4

%

 

1.3

%

 

1.4

%

Expected stock price volatility

 

 

36.7

%

 

37.3

%

 

37.6

%

Risk-free interest rate

 

 

1.6

%

 

2.0

%

 

3.3

%

Expected life of options

 

 

7 years

 

 

6 years

 

 

7 years