Shareholders' Equity (Tables)

12 Months Ended

Dec. 31, 2015

The following table summarizes by repurchase plan the Company’s repurchasing activity:



	Cumulative shares repurchased	Average price per share
Non-Discretionary Plan (1994 through 2015)	30,231	$	27.58
Discretionary Plan (2001 through 2015)	54,471	$	39.98

The following table summarizes information about stock options:



	Number of shares		Weighted average exercise price per share		Weighted average remaining contractual life	Aggregate intrinsic value
Outstanding at December 31, 2014	19,372		$	41.92
Options granted	2,956		$	47.27
Options exercised	(2,819	)	$	37.33
Options forfeited	(593	)	$	42.21
Options canceled	(184	)	$	47.88
Outstanding at December 31, 2015	18,732		$	43.39	5.84	$	60,057
Exercisable at December 31, 2015	8,918		$	44.36	3.44	$	23,546

The fair value of each option grant is estimated on the date of grant using the Black-Scholes option pricing model with the following assumptions:



	For the years ended December 31,
	2015			2014			2013
Dividend yield	1.60			1.50 - 1.51%			1.50 - 1.53%
Volatility – stock option plans	29 - 34%			35 - 36%			38%
Volatility – stock purchase rights plans	20		%	20		%	21		%
Risk-free interest rates	0.30 - 2.04%			0.11 - 2.27%			0.12 - 1.40%
Expected life (years) – stock option plans	6.41 - 7.47			6.52 - 7.43			5.91 - 7.43
Expected life (years) – stock purchase rights plans	1			1			1
Weighted average fair value of stock options granted during the period	$	13.44		$	14.44		$	11.17
Weighted average fair value of stock purchase rights granted during the period	$	10.45		$	9.60		$	9.43

Total stock compensation expense and the total related tax benefit recognized are as follows: