The amount, timing and frequency of future distributions will be at the sole discretion of our Board of Directors and will be declared based upon various factors, a number of which may be beyond our control, including our financial condition and operating cash flows, the amount required to maintain our qualification for taxation as a REIT and reduce any income and excise taxes that we otherwise would be required to pay, limitations on distributions in our existing and future debt and preferred equity instruments, our ability to utilize NOLs to offset our distribution requirements, limitations on our ability to fund distributions using cash generated through our TRSs and other factors that our Board of Directors may deem relevant.
During the year ended December 31, 2014, we declared an aggregate of $554.6 million in regular cash distributions to our common stockholders, which included our fourth quarter distribution of $0.38 per share (approximately $150.7 million) payable on January 13, 2015 to common stockholders of record at the close of business on December 16, 2014.
During the year ended December 31, 2014, we declared an aggregate of $23.9 million in cash distributions to our preferred stockholders, which included a dividend of $1.3125 per share (approximately $7.9 million), payable on February 16, 2015 to preferred stockholders of record at the close of business on February 1, 2015.
We accrue distributions on unvested restricted stock unit awards granted subsequent to January 1, 2012, which are payable upon vesting.
As of December 31, 2014, the amount accrued for distributions payable related to unvested restricted stock units was $3.4 million.
During the year ended December 31, 2014, we paid $0.7 million of distributions upon the vesting of restricted stock units.
For more details on the regular cash distributions paid to our common stockholders during the year ended December 31, 2014, see note 16 to our consolidated financial statements included in this Annual Report.
Contractual Obligations.
The following table summarizes our contractual obligations as of December 31, 2014 (in thousands): Contractual Obligations
## Table 0 ##
PART II ITEM 5.
MARKET FOR REGISTRANT’S COMMON EQUITY, RELATED STOCKHOLDER MATTERS AND ISSUER PURCHASES OF EQUITY SECURITIES The following table presents reported quarterly high and low per share sale prices of our common stock on the NYSE for the years 2016 and 2015.
## Table 1 ##
On February 17, 2017, the closing price of our common stock was $108.11 per share as reported on the NYSE.
As of February 17, 2017, we had 427,195,037 outstanding shares of common stock and 153 registered holders.
Dividends As a REIT, we must annually distribute to our stockholders an amount equal to at least 90% of our REIT taxable income (determined before the deduction for distributed earnings and excluding any net capital gain).
Generally, we have distributed and expect to continue to distribute all or substantially all of our REIT taxable income after taking into consideration our utilization of net operating losses (“NOLs”).
We have two series of preferred stock outstanding, 5.25% Mandatory Convertible Preferred Stock, Series A (the “Series A Preferred Stock”), issued in May 2014, with a dividend rate of 5.25%, and the 5.50% Mandatory Convertible Preferred Stock, Series B (the “Series B Preferred Stock”), issued in March 2015, with a dividend rate of 5.50%.
Dividends are payable quarterly in arrears, subject to declaration by our Board of Directors.
The amount, timing and frequency of future distributions will be at the sole discretion of our Board of Directors and will depend upon various factors, a number of which may be beyond our control, including our financial condition and operating cash flows, the amount required to maintain our qualification for taxation as a REIT and reduce any income and excise taxes that we otherwise would be required to pay, limitations on distributions in our existing and future debt and preferred equity instruments, our ability to utilize NOLs to offset our distribution requirements, limitations on our ability to fund distributions using cash generated through our TRSs and other factors that our Board of Directors may deem relevant.
We have distributed an aggregate of approximately $3.2 billion to our common stockholders, including the dividend paid in January 2017, primarily subject to taxation as ordinary income.
## Table 2 ##
(1) For the years ended December 31, 2016, 2015, 2014, 2013 and 2012, amount includes unrealized foreign currency losses of $23.4 million, $71.5 million, $49.3 million, $211.7 million and $34.3 million, respectively.
(2) For the purpose of this calculation, “earnings” consists of income from continuing operations before income taxes and income on equity method investments, as well as fixed charges (excluding interest capitalized and amortization of interest capitalized).
“Fixed charges” consists of interest expensed and capitalized, amortization of debt discounts, premiums and related issuance costs and the component of rental expense associated with operating leases believed by management to be representative of the interest factor thereon.
(3) Balances have been revised to reflect debt issuance cost adjustments.
(4) Balances have been revised to reflect purchase accounting measurement period adjustments for the years ended December 31, 2014, 2013 and 2012.
(5) As of December 31, 2016, 2015, 2014, 2013 and 2012, amount includes $149.3 million, $142.2 million, $160.2 million, $152.9 million and $69.3 million, respectively, of restricted funds pledged as collateral to secure obligations and cash, the use of which is otherwise limited by contractual provisions.
ITEM 7.
MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS The discussion and analysis of our financial condition and results of operations that follow are based upon our consolidated financial statements, which have been prepared in accordance with GAAP.
The preparation of our financial statements requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities, revenues and expenses and the related disclosure of contingent assets and liabilities at the date of our financial statements.
Actual results may differ from these estimates and such differences could be material to the financial statements.
This discussion should be read in conjunction with our consolidated financial statements included in this Annual Report and the accompanying notes, and the information set forth under the caption “Critical Accounting Policies and Estimates” below.
We report our results in five segments: U. S.  property, Asia property, EMEA property, Latin America property and Services.
In evaluating financial performance in each business segment, management uses, among other factors, segment gross margin and segment operating profit (see note 20 to our consolidated financial statements included in this Annual Report).
Executive Overview We are one of the largest global REITs and a leading independent owner, operator and developer of multitenant communications real estate.
Our primary business is the leasing of space on communications sites to wireless service providers, radio and television broadcast companies, wireless data providers, government agencies and municipalities and tenants in a number of other industries.
In addition to the communications sites in our portfolio, we manage rooftop and tower sites for property owners under various contractual arrangements.
We also hold other telecommunications infrastructure and property interests that we lease to communications service providers and third-party tower operators.
We refer to this business as our property operations, which accounted for 99% of our total revenues for the year ended December 31, 2016 and includes our U. S.  property segment, Asia property segment, EMEA property segment and Latin America property segment.
We also offer tower-related services, including site acquisition, zoning and permitting and structural analysis services, which primarily support our site leasing business, including the addition of new tenants and equipment on our sites.

<table><tr><td> Contractual Obligations</td><td> 2015</td><td> 2016</td><td> 2017</td><td> 2018</td><td> 2019</td><td> Thereafter</td><td> Total</td></tr><tr><td>Long-term debt, including current portion:</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td><i>American Tower subsidiary debt:</i></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>Secured Tower Revenue Securities, Series 2013-1A-1</td><td>$—</td><td>$—</td><td>$—</td><td>$500,000</td><td>$—</td><td>$—</td><td>$500,000</td></tr><tr><td>Secured Tower Revenue Securities, Series 2013-2A-2</td><td>—</td><td>—</td><td>—</td><td>—</td><td>—</td><td>1,300,000</td><td>1,300,000</td></tr><tr><td>GTP Notes-3</td><td>4,935</td><td>720,640</td><td>93,503</td><td>245,000</td><td>172,987</td><td>—</td><td>1,237,065</td></tr><tr><td>BR Towers Debentures-4</td><td>5,623</td><td>8,026</td><td>9,904</td><td>11,428</td><td>15,978</td><td>67,728</td><td>118,687</td></tr><tr><td>BR Towers Credit Facility-4</td><td>1,198</td><td>2,874</td><td>2,874</td><td>2,874</td><td>2,874</td><td>3,695</td><td>16,389</td></tr><tr><td>Unison Notes, Series 2010-1 Class C, Series 2010-2 Class C and Series 2010-2 Class F notes-5</td><td>—</td><td>—</td><td>67,000</td><td>—</td><td>—</td><td>129,000</td><td>196,000</td></tr><tr><td>Mexican loan-6</td><td>263,426</td><td>—</td><td>—</td><td>—</td><td>—</td><td>—</td><td>263,426</td></tr><tr><td>South African Facility-7</td><td>9,448</td><td>13,145</td><td>14,788</td><td>15,610</td><td>17,253</td><td>4,889</td><td>75,133</td></tr><tr><td>Colombian Credit Facility-8</td><td>4,180</td><td>8,360</td><td>12,539</td><td>12,539</td><td>12,539</td><td>33,439</td><td>83,596</td></tr><tr><td>Shareholder Loans-9</td><td>—</td><td>—</td><td>—</td><td>—</td><td>137,655</td><td>—</td><td>137,655</td></tr><tr><td>Total American Tower subsidiary debt</td><td>288,810</td><td>753,045</td><td>200,608</td><td>787,451</td><td>359,286</td><td>1,538,751</td><td>3,927,951</td></tr><tr><td><i>American Tower Corporation debt:</i></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>2013 Credit Facility</td><td>—</td><td>—</td><td>—</td><td>—</td><td>—</td><td>—</td><td>—</td></tr><tr><td>2013 Term Loan</td><td>—</td><td>—</td><td>—</td><td>—</td><td>1,500,000</td><td>—</td><td>1,500,000</td></tr><tr><td>2014 Credit Facility</td><td>—</td><td>—</td><td>—</td><td>—</td><td>—</td><td>1,100,000</td><td>1,100,000</td></tr><tr><td>4.625% senior notes-10</td><td>600,000</td><td>—</td><td>—</td><td>—</td><td>—</td><td>—</td><td>600,000</td></tr><tr><td>7.00% senior notes</td><td>—</td><td>—</td><td>500,000</td><td>—</td><td>—</td><td>—</td><td>500,000</td></tr><tr><td>4.50% senior notes</td><td>—</td><td>—</td><td>—</td><td>1,000,000</td><td>—</td><td>—</td><td>1,000,000</td></tr><tr><td>3.40% senior notes</td><td>—</td><td>—</td><td>—</td><td>—</td><td>1,000,000</td><td>—</td><td>1,000,000</td></tr><tr><td>7.25% senior notes</td><td>—</td><td>—</td><td>—</td><td>—</td><td>300,000</td><td>—</td><td>300,000</td></tr><tr><td>5.05% senior notes</td><td>—</td><td>—</td><td>—</td><td>—</td><td>—</td><td>700,000</td><td>700,000</td></tr><tr><td>3.450% senior notes</td><td>—</td><td>—</td><td>—</td><td>—</td><td>—</td><td>650,000</td><td>650,000</td></tr><tr><td>5.90% senior notes</td><td>—</td><td>—</td><td>—</td><td>—</td><td>—</td><td>500,000</td><td>500,000</td></tr><tr><td>4.70% senior notes</td><td>—</td><td>—</td><td>—</td><td>—</td><td>—</td><td>700,000</td><td>700,000</td></tr><tr><td>3.50% senior notes</td><td>—</td><td>—</td><td>—</td><td>—</td><td>—</td><td>1,000,000</td><td>1,000,000</td></tr><tr><td>5.00% senior notes</td><td>—</td><td>—</td><td>—</td><td>—</td><td>—</td><td>1,000,000</td><td>1,000,000</td></tr><tr><td>Total American Tower Corporation debt</td><td>600,000</td><td>—</td><td>500,000</td><td>1,000,000</td><td>2,800,000</td><td>5,650,000</td><td>10,550,000</td></tr></table>
<table><tr><td>2016</td><td>High</td><td>Low</td></tr><tr><td>Quarter ended March 31</td><td>$102.93</td><td>$83.07</td></tr><tr><td>Quarter ended June 30</td><td>113.63</td><td>101.87</td></tr><tr><td>Quarter ended September 30</td><td>118.26</td><td>107.57</td></tr><tr><td>Quarter ended December 31</td><td>118.09</td><td>99.72</td></tr><tr><td>2015</td><td>High</td><td>Low</td></tr><tr><td>Quarter ended March 31</td><td>$101.88</td><td>$93.21</td></tr><tr><td>Quarter ended June 30</td><td>98.64</td><td>91.99</td></tr><tr><td>Quarter ended September 30</td><td>101.54</td><td>86.83</td></tr><tr><td>Quarter ended December 31</td><td>104.12</td><td>87.23</td></tr></table>
<table><tr><td></td><td colspan="5">As of December 31,</td></tr><tr><td></td><td>2016</td><td>2015</td><td>2014 -3</td><td>2013 -3</td><td>2012 -3</td></tr><tr><td></td><td colspan="5">(In thousands)</td></tr><tr><td>Balance Sheet Data: -4</td><td colspan="5"></td></tr><tr><td>Cash and cash equivalents (including restricted cash) (5)</td><td>$936,442</td><td>$462,879</td><td>$473,698</td><td>$446,492</td><td>$437,934</td></tr><tr><td>Property and equipment, net</td><td>10,517,258</td><td>9,866,424</td><td>7,590,112</td><td>7,177,728</td><td>5,765,856</td></tr><tr><td>Total assets</td><td>30,879,150</td><td>26,904,272</td><td>21,263,565</td><td>20,213,937</td><td>14,045,810</td></tr><tr><td>Long-term obligations, including current portion</td><td>18,533,465</td><td>17,119,009</td><td>14,540,341</td><td>14,408,550</td><td>8,709,757</td></tr><tr><td>Redeemable noncontrolling interest</td><td>1,091,220</td><td>—</td><td>—</td><td>—</td><td>—</td></tr><tr><td>Total American Tower Corporation equity</td><td>6,763,895</td><td>6,651,679</td><td>3,953,560</td><td>3,534,165</td><td>3,573,101</td></tr></table>

Question: Between 2017 and 2018, which year is Total American Tower subsidiary debt the lowest ?
Answer: 2017