EQUITY INCENTIVE PLAN

The Company’s equity incentive plan provides employees and directors of the Company additional incentives to join and/or remain in the service of the Company as well as to maintain and enhance the long-term performance and profitability of the Company. The Company’s 2013 equity incentive plan was approved by shareholders on May 2, 2013 and provides that 2 million shares of common stock, plus any options outstanding under the Company’s prior option plan that terminate without being exercised, may be the subject of awards. The plan provides for the grant of options, restricted stock, restricted stock units and other equity-based awards. The exercise price of options granted shall not be less than the fair market value of the common stock on the date of the award. Options primarily vest equally over a five-year period from the date of grant and have a maximum term of up to ten years and six months. Restricted units primarily vest equally over a five-year period from the date of grant. Since 2005, the compensation committee of the Board of Directors has generally granted restricted share units to participating managers and non-qualified stock options to executive officers.

All share-based compensation arrangements granted to employees, including stock option grants, are recognized in the consolidated statement of operations based on the grant-date fair value of the award over the period during which an employee is required to provide service in exchange for the award. Share-based compensation expense is recorded within selling, general, and administrative in the consolidated statement of operations with a corresponding offset to additional paid-in capital in the consolidated balance sheet.

The fair values of stock options granted were calculated using the Black-Scholes pricing model. The aggregate intrinsic value of an option is the amount by which the fair value of the underlying stock exceeds its exercise price. The following table summarizes all stock option activity from December 31, 2014 through December 31, 2015:



	Number of Options		Weighted Average Exercise Price	Aggregate Intrinsic Value (in millions)
Outstanding at December 31, 2014	1,646,483		$133.80	$277.7
Granted	108,694		312.36
Exercised	(372,355	)	79.37
Forfeited	(8,117	)	208.17
Outstanding at December 31, 2015	1,374,705		$162.29	$243.1
Options exercisable at December 31, 2015	1,000,773		$130.15	$209.1

The following table details the weighted average remaining contractual life of options outstanding at December 31, 2015 by range of exercise prices:



Number of Options Outstanding	Weighted Average Exercise Price		Remaining Contractual Life of Options Outstanding	Options Exercisable
Number of Options Outstanding	Weighted Average Exercise Price		Remaining Contractual Life of Options Outstanding	Options Exercisable
294,206	$	84.18	3.4	294,206
202,950	$	109.00	1.9	202,950
340,650	$	141.50	5.3	309,259
173,273	$	169.37	6.8	109,023
363,626	$	271.34	8.8	85,335
1,374,705			5.5	1,000,773

As of the date granted, the weighted average grant-date fair value of the options granted during the years ended December 31, 2015, 2014, and 2013 was $92.81, $77.64, and $66.33, respectively.

Such weighted average grant-date fair value was determined using the following assumptions:



	2015		2014		2013
Risk-free interest rate	1.65	%	1.66	%	1.31	%
Expected life in years	5.7		5.6		5.0
Expected volatility	28	%	28	%	28	%
Expected dividend yield	—		—		—

The total intrinsic value of options exercised during the years ended December 31, 2015, 2014, and 2013 was approximately $90.7 million, $66.9 million, and $60.0 million, respectively.

The total fair value of options vested during the years ended December 31, 2015, 2014, and 2013 was approximately $8.6 million, $6.4 million, and $5.7 million, respectively.

The following table summarizes all restricted stock unit activity from December 31, 2014 through December 31, 2015:



	Number of Restricted Stock Units		Aggregate Intrinsic Value (in millions)
Outstanding at December 31, 2014	96,097		$	29.1
Granted	25,970
Vested	(31,553	)
Forfeited	(8,440	)
Outstanding at December 31, 2015	82,074		$	27.8

The weighted average grant-date fair value of the restricted stock units granted during years ended 2015 and 2014 was $312.57 and $263.58 per unit, respectively, and the restricted units vest ratably primarily over a five-year period. The total fair value of the restricted stock units on the date of grant of $8.1 million for 2015 and $7.8 million for 2014 will be recorded as compensation expense on a straight-line basis over the vesting period. The total fair value of restricted stock units vested during the years ended December 31, 2015, 2014, and 2013 was approximately $6.0 million, $5.8 million, and $5.6 million, respectively. Approximately $5.8 million and $5.6 million of compensation expense was recognized during the years ended December 31, 2015 and 2014, respectively.

At December 31, 2015, a total of 2,448,666 shares of common stock were available for grant in the form of stock options or restricted stock units.

As of December 31, 2015, the unrecorded deferred share-based compensation balance related to both stock options and restricted stock units was $44.9 million and will be recognized using a straight-line method over an estimated weighted average amortization period of 2.3 years.