Shareholders' Equity (Tables)

12 Months Ended

Dec. 31, 2018

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



	Cumulative shares repurchased	Average price per share
Non-Discretionary Plan (1994 through 2018)	39,912	$	35.20
Discretionary Plan (2001 through 2018)	68,743	$	44.66

The following table summarizes information about RSU:



	Number of shares		Weighted average grant date fair value
Outstanding at December 31, 2017	581		$	54.11
RSU granted	466		$	69.58
RSU vested	(193	)	$	54.17
RSU forfeited	(20	)	$	60.78
Outstanding at December 31, 2018	834		$	62.51

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, 2017	12,961		$	44.36
Options granted	—		$	—
Options exercised	(3,422	)	$	43.68
Options forfeited	(152	)	$	45.68
Options canceled	(34	)	$	43.36
Outstanding at December 31, 2018	9,353		$	44.60	5.13	$	219,719
Exercisable at December 31, 2018	6,570		$	43.89	4.55	$	158,995

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



	For the years ended December 31,
	2018			2017			2016
Dividend yield	1.30		%	1.50		%	1.70		%
Volatility – stock option plans	—			—			24 - 25%
Volatility – stock purchase rights plans	22		%	14		%	20		%
Risk-free interest rates	1.30		%	1.22		%	0.51 - 1.42%
Expected life (years) – stock option plans	—			—			5.5 - 6.5
Expected life (years) – stock purchase rights plans	1			1			1
Weighted average fair value of stock options granted during the period	$	—		$	—		$	9.57
Weighted average fair value of stock purchase rights granted during the period	$	17.49		$	11.69		$	10.99