XML 57 R31.htm IDEA: XBRL DOCUMENT v2.4.0.8
Description of the Business, Basis of Presentation and Summary of Significant Accounting Policies (Tables)
12 Months Ended
May 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]  
Schedule of assumptions used in valuation of share-based compensation awards
The table set forth below provides the estimated fair value of options granted by the Company during fiscal years 2014, 2013 and 2012 and the significant weighted average assumptions used in determining such fair value under the Black-Scholes option pricing model. The average expected life represents an estimate of the period of time stock options are expected to remain outstanding based on the historical exercise behavior of the option grantees. The risk-free interest rate was based on the U.S. Treasury yield curve corresponding to the expected life in effect at the time of the grant. The volatility was estimated based on historical volatility corresponding to the expected life.
 
 
2014
 
2013
 
2012
Estimated fair value of stock options granted
$
10.37

 
$
9.77

 
$
9.30

Assumptions:
 

 
 

 
 

Expected dividend yield
1.7
%
 
1.6
%
 
1.4
%
Expected stock price volatility
38.6
%
 
37.5
%
 
36.7
%
Risk-free interest rate
2.2
%
 
0.9
%
 
1.6
%
Expected life of options
6 years

 
6 years

 
7 years