Annual report pursuant to Section 13 and 15(d)

Accounting Policies Stock Option Assumptions (Tables)

v3.8.0.1
Accounting Policies Stock Option Assumptions (Tables)
12 Months Ended
Dec. 31, 2017
Share-based Compensation [Abstract]  
Schedule of Share-based Payment Award, Valuation Assumptions [Table Text Block]
The following table contains the weighted-average assumptions used to estimate the fair value of options granted.  These assumptions are subjective and changes in these assumptions can materially affect the fair value estimate.

December 31,
2017

December 31,
2016

December 31,
2015
Expected dividend yield
1.3
%

1.0
%

1.0
%
Expected stock price volatility
28.5
%

28.9
%

33.3
%
Weighted average risk-free interest rate
2.0
%

1.3
%

1.6
%
Expected life of options (years)
5.9


5.8


5.9


The fair value of non-vested shares issued were estimated using the closing market prices for the business day of the grant. The share-based compensation for the non-vested shares is recognized ratably over the requisite service period or vesting period.

The fair value of the performance shares was estimated using a Monte Carlo simulation. The share-based compensation for performance shares are recognized ratably over the requisite service period, or vesting period. The following table contains the weighted-average assumptions used to estimate the fair value of performance shares granted.  These assumptions are subjective and changes in these assumptions can materially affect the fair value estimate.

 
 
Year ended
 
 

December 31,
2017
 
December 31,
2016

December 31,
2015
Expected stock price volatility
24.7
%
 
22.3
%

23.5
%
Weighted average risk-free interest rate
1.4
%
 
0.8
%

1.0
%