Item 6. SELECTED FINANCIAL DATA

	Year Ended December 31,
(In thousands, except per share amounts)	2018			2017		2016		2015		2014
Operating Data:
Revenue from operations	$	4,043,695		$	3,358,112	$	2,991,517	$	2,972,442	$	2,787,897
Depreciation and amortization expense		230,357			205,763		189,867		165,343		146,466
Total operating expenses		3,226,644			2,782,226		2,507,682		2,474,202		2,346,590
Operating income		817,051			575,886		483,835		498,240		441,307
Interest (income) expense, net		(2,924	)		1,414		4,274		5,001		6,502
Provision for income taxes		209,845			112,058		181,822		185,327		165,000
Net income (1)		605,668			463,774		295,765		304,690		267,514

Per Share Data:
Basic earnings per share	$	7.39		$	5.63	$	3.56	$	3.57	$	3.10
Diluted earnings per share	$	7.38		$	5.63	$	3.56	$	3.57	$	3.10
Cash dividends per share	$	0.52		$	0.40	$	—	$	—	$	—

Balance Sheet Data:
Cash and cash equivalents	$	190,282		$	127,462	$	10,171	$	11,472	$	34,787
Current assets		706,229			584,653		382,622		381,730		403,772
Total assets		3,545,283			3,068,424		2,696,247		2,466,504		2,206,866
Current liabilities		356,732			351,049		288,636		285,402		255,638
Long-term debt (including current maturities)		45,000			95,000		104,975		133,805		155,714
Shareholders’ equity		2,680,483			2,276,854		1,851,158		1,684,637		1,494,064

(1)	Our 2017 net income includes a provisional tax benefit of $104.9 million due to the remeasurement of our deferred taxes to reflect the impact of the Tax Act.