The selected consolidated financial data presented below is derived from the Consolidated Financial Statements and related Notes of the Company, and should be read in connection with those statements, some of which are included herein. Selected financial data reflects results of any acquired business from the date of acquisition, including data related to the Momondo Group from its acquisition date of July 24, 2017, FareHarbor from its acquisition date of April 26, 2018 and HotelsCombined from its acquisition date of November 30, 2018. The information set forth below is not necessarily indicative of future results and should be read in conjunction with Part II, Item 7, Management's Discussion and Analysis of Financial Condition and Results of Operations.
Year Ended December 31,
2019**(1)**
2018**(1)**
2017
2016
2015
(In millions, except per share amounts)
Total revenues
$
15,066
$
14,527
$
12,681
$
10,743
$
9,224
Cost of revenues
N/A
N/A
242
415
646
Gross profit
N/A
N/A
12,439
10,328
8,578
Total operating expenses (2)
9,721
9,186
7,901
7,422
5,319
Operating income (2)
5,345
5,341
4,538
2,906
3,259
Total other income (expense) (3)
613
(506
)
(139
)
(193
)
(131
)
Income tax expense (4)
1,093
837
2,058
578
577
Net income (2) (3) (4)
4,865
3,998
2,341
2,135
2,551
Net income applicable to common stockholders per basic common share (2) (3) (4)
112.93
84.26
47.78
43.14
50.09
Net income applicable to common stockholders per diluted common share (2) (3) (4)
111.82
83.26
46.86
42.65
49.45
Total assets (5)
21,402
22,687
25,451
19,839
17,421
Long-term obligations (5) (6)
11,091
10,347
11,403
8,128
7,186
Total liabilities (5)
15,469
13,902
14,187
9,990
8,626
Total stockholders' equity
5,933
8,785
11,261
9,820
8,795
(1)
The financial statements for the years ended December 31, 2019 and 2018 are presented in accordance with the current revenue recognition accounting standard adopted on January 1, 2018. Financial statements for all periods prior to January 1, 2018 are presented under the previous revenue recognition accounting standard. Under the current revenue recognition standard, we no longer present "Cost of revenues" or "Gross profit" in our Consolidated Statements of Operations. Therefore total revenues reported in 2019 and 2018 are comparable to gross profit reported in previous years. See Note 2 to our Consolidated Financial Statements for further information.
(2)
Includes a non-cash charge related to an impairment of OpenTable goodwill of $941 million, which is not tax deductible, for the year ended December 31, 2016. The goodwill impairment charge reduced the 2016 basic and diluted net income per share by $19.01 and $18.79, respectively.
(3)
Includes net unrealized gains on marketable equity securities of $745 million for the year ended December 31, 2019 and net unrealized losses on marketable equity securities of $367 million for the year ended December 31, 2018. The unrealized gains (losses) on marketable equity securities, net of tax, increased the 2019 basic and diluted net income per share by $13.52 and $13.39, respectively, and reduced the 2018 basic and diluted net income per share by $6.50 and $6.42, respectively. Pursuant to the adoption of the accounting update on financial instruments in 2018, for periods beginning after December 31, 2017, changes in fair value of marketable equity securities are recognized in net income rather than "Accumulated other comprehensive loss" in the Consolidated Balance Sheets. See Note 2 to our Consolidated Financial Statements for further information.
(4)
Includes income tax benefits of $17 million and $46 million for the years ended December 31, 2019 and 2018, respectively, to adjust the 2017 provisional tax expense related to a one-time transitional tax on mandatory deemed repatriation of accumulated unremitted international earnings as a result of the U.S. Tax Cuts and Jobs Act (“Tax Act”) enacted in December 2017 (see Note 15 to the Consolidated Financial Statements). The income tax provision for the
year ended December 31, 2017 includes a provisional tax expense of $1.6 billion related to the transition tax mentioned above and a provisional net tax benefit of $217 million related to the remeasurement of the Company’s U.S. deferred tax assets and liabilities as a result of the Tax Act, which reduced the 2017 basic and diluted net income per share by $27.47 and $26.94, respectively.
(5)
Includes, as applicable, operating lease assets of $620 million, current operating lease liabilities of $161 million and non-current operating lease liabilities of $462 million that are reported in the Consolidated Balance Sheet at December 31, 2019. Operating lease assets and liabilities are recognized in the balance sheet as a result of the adoption of the current lease standard on January 1, 2019. See Notes 2 and 10 to our Consolidated Financial Statements for further information.
(6)
Includes convertible debt which is classified as a current liability, when applicable.