Item 6.
SELECTED FINANCIAL DATA The following table sets forth selected historical financial data of PCA (dollars and shares in millions, except per share data).
The information contained in the table should be read in conjunction with the disclosures in “Part II, Item 7.
Management’s Discussion and Analysis of Financial Condition and Results of Operations” and “Part II, Item 8.
Financial Statements and Supplementary Data” of this Form 10-K.
## Table 0 ##
(a) Effective January 1, 2016, the Company adopted Accounting Standards Update (ASU) 2015-03 (Topic 835): Simplifying the Presentation of Debt Issuance Costs.
We applied this guidance retrospectively, as required, and reclassified the debt issuance costs from “Other long-term assets” to “Long-term debt” on our Consolidated Balance Sheet to conform with current period presentation.
Total assets for all periods presented have been updated to reflect this adoption.
Effective December 31, 2015, the Company adopted Accounting Standards Update 2015-17, Balance Sheet Classification of Deferred Taxes.
The guidance eliminates the requirement to classify deferred taxes between current and noncurrent and requires that all deferred tax assets and liabilities, along with any related valuation allowance, be classified as noncurrent on the balance sheet.
Our total assets for all periods presented have been updated to reflect this adoption.
Effective January 1, 2014, the Company changed its method of accounting for inventories from lower of cost, as determined by the LIFO method, or market, to lower of cost, as determined by the average cost method, or market.
The Company applied the change retrospectively to all prior periods presented herein in accordance with US generally accepted accounting principles (GAAP) relating to accounting changes.
Net income and net income per common share are impacted by a lower U. S.  corporate federal statutory income tax rate of 21% in 2018 and 35% in in all prior years presented in this table.
In addition, both 2018 and 2017 include a tax benefit of $2.0 million and $122.1 million, respectively, related to the enactment in December 2017 of the Tax Cuts and Jobs Act (H. R. 1).
See Note 7, Income Taxes, for more information.
freight ($13 million), converting and other costs ($8 million), and higher depreciation expense ($12 million).
Special items in 2017 included expense of $5 million for property damage and business interruption insurance deductible related to the DeRidder mill incident, $2 million in integration-related costs, and $11 million in net gains related to facility closures and land sales, an adjustment to Hexacomb working capital, and the expiration of a repurchase option corresponding to timberland previously sold.
Special items in 2016 included $9 million of facility closure costs, $4 million of TimBar and Columbus Container acquisition-related costs, and $1 million related to our withdrawal from a multiemployer pension plan for one of our corrugated products facilities.
Paper.
Segment income from operations decreased $78 million to $54 million, compared to $132 million in 2016.
The decrease primarily related to lower sales and production volumes ($17 million), lower paper prices and mix ($8 million), and higher costs for energy ($12 million) and annual outage expenses ($10 million).
Special items during 2017 included expense of $33 million related to the conversion of the Wallula No.3 machine to kraft linerboard, compared to $4 million related to the shutdown of market pulp operations at our Wallula mill and facilities closures in 2016.
Interest Expense, Net and Other, and Income Taxes Interest expense, net and other, during 2017 increased $9 million compared to 2016.
The increase in interest expense was primarily due to interest on term loan borrowings for the TimBar acquisition made in August 2016, higher interest rates on variable rate debt due to higher LIBOR in 2017 compared to 2016, and interest on the new notes related to the December 2017 refinancing.
During 2017, income tax expense decreased $79 million compared to 2016 primarily due to a $122.1 million tax benefit as a result of H. R.  1 (P. L.  115-97), originally known as the “Tax Cuts and Jobs Act” (the “Tax Act”), which the President signed into law on December 22, 2017.
The effective tax rate for 2017 and 2016 was 19.3% and 34.7%, respectively.
For additional information regarding the impact of the Tax Act, see Note 7, Income Taxes, in “Part II, Item 8.
Financial Statements and Supplementary Data” of this Form 10-K.
Liquidity and Capital Resources Sources and Uses of Cash Our primary sources of liquidity are net cash provided by operating activities and available borrowing capacity under our revolving credit facility.
We ended the year with $362 million of cash and $327 million of unused borrowing capacity under the revolving credit facility, net of letters of credit.
Currently, our primary uses of cash are for operations, capital expenditures, acquisitions, debt service, common stock dividends, and repurchases of common stock.
We believe that net cash generated from operating activities, cash on hand, available borrowings under our revolving credit facility and available capital through access to capital markets will be adequate to meet our liquidity and capital requirements, including payments of any declared common stock dividends, for the foreseeable future.
As our debt or credit facilities become due, we will need to repay, extend or replace such facilities.
Our ability to do so will be subject to future economic conditions and financial, business, and other factors, many of which are beyond our control.
Below is a summary table of our cash flows, followed by a discussion of our sources and uses of cash through operating activities, investing activities, and financing activities (dollars in millions):
## Table 1 ##
Sacramento Container Acquisition In October 2017, PCA acquired substantially all of the assets of Sacramento Container Corporation, and 100% of the membership interests of Northern Sheets, LLC and Central California Sheets, LLC (collectively referred to as “Sacramento Container”) for a purchase price of $274 million, including working capital adjustments.
Funding for the acquisition came from available cash on hand.
Assets acquired include full-line corrugated products and sheet feeder operations in both McClellan, California and Kingsburg, California.
Sacramento Container provides packaging solutions to customers serving portions of California’s strong agricultural market.
Sacramento Container’s financial results are included in the Packaging segment from the date of acquisition.
The Company accounted for the Sacramento Container acquisition using the acquisition method of accounting in accordance with ASC 805, Business Combinations.
The total purchase price has been allocated to tangible and intangible assets acquired and liabilities assumed based on respective fair values, as follows (dollars in millions):
## Table 2 ##
During the second quarter ended June 30, 2018, we made a $5.5 million net adjustment based on the final valuation of the intangible assets.
We recorded the adjustment as a decrease to other intangible assets with an offset to goodwill.
Goodwill is calculated as the excess of the purchase price over the fair value of the net assets acquired.
Among the factors that contributed to the recognition of goodwill were Sacramento Container’s commitment to continuous improvement and regional synergies, as well as the expected increases in PCA’s containerboard integration levels.
Goodwill is deductible for tax purposes.
Other intangible assets, primarily customer relationships, were assigned an estimated weighted average useful life of 9.6 years.
Property, plant and equipment were assigned estimated useful lives ranging from one to 13 years.

<table><tr><td></td><td colspan="5">Year Ended December 31,</td></tr><tr><td></td><td>2018</td><td>2017</td><td>2016</td><td>2015</td><td>2014</td></tr><tr><td>Statement of Income Data (a):</td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>Net Sales</td><td>$7,014.6</td><td>$6,444.9</td><td>$5,779.0</td><td>$5,741.7</td><td>$5,852.6</td></tr><tr><td>Net Income</td><td>738.0</td><td>668.6</td><td>449.6</td><td>436.8</td><td>392.6</td></tr><tr><td>Net income per common share:</td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>— basic</td><td>7.82</td><td>7.09</td><td>4.76</td><td>4.47</td><td>3.99</td></tr><tr><td>— diluted</td><td>7.80</td><td>7.07</td><td>4.75</td><td>4.47</td><td>3.99</td></tr><tr><td>Weighted average common shares outstanding:</td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>— basic</td><td>93.7</td><td>93.5</td><td>93.5</td><td>96.6</td><td>97.0</td></tr><tr><td>— diluted</td><td>93.9</td><td>93.7</td><td>93.7</td><td>96.7</td><td>97.1</td></tr><tr><td>Cash dividends declared per common share</td><td>3.00</td><td>2.52</td><td>2.36</td><td>2.20</td><td>1.60</td></tr><tr><td>Balance Sheet Data (a):</td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>Total assets</td><td>$6,569.7</td><td>$6,197.5</td><td>$5,777.0</td><td>$5,272.3</td><td>$5,258.7</td></tr><tr><td>Total debt obligations</td><td>2,502.7</td><td>2,650.7</td><td>2,667.4</td><td>2,319.7</td><td>2,365.2</td></tr><tr><td>Stockholders' equity</td><td>2,672.4</td><td>2,182.6</td><td>1,759.8</td><td>1,633.3</td><td>1,521.4</td></tr></table>
<table><tr><td></td><td colspan="3">Year Ended December 31,</td></tr><tr><td></td><td>2018</td><td>2017</td><td>2016</td></tr><tr><td>Net cash provided by (used for):</td><td></td><td></td><td></td></tr><tr><td>Operating activities</td><td>$1,180.1</td><td>$856.1</td><td>$806.9</td></tr><tr><td>Investing activities</td><td>-608.2</td><td>-609.1</td><td>-769.6</td></tr><tr><td>Financing activities</td><td>-427.3</td><td>-269.4</td><td>17.8</td></tr><tr><td>Net increase (decrease) in cash and cash equivalents</td><td>$144.6</td><td>$-22.4</td><td>$55.1</td></tr></table>
<table><tr><td></td><td>12/31/17 Allocation</td><td>Adjustments</td><td>Revised Allocation</td></tr><tr><td>Goodwill</td><td>$151.1</td><td>$5.5</td><td>$156.6</td></tr><tr><td>Other intangible assets</td><td>72.6</td><td>-5.5</td><td>67.1</td></tr><tr><td>Property, plant and equipment</td><td>26.7</td><td>—</td><td>26.7</td></tr><tr><td>Other net assets</td><td>23.4</td><td>—</td><td>23.4</td></tr><tr><td>Net assets acquired</td><td>$273.8</td><td>$—</td><td>$273.8</td></tr></table>

Question: Which year has the greatest proportion of — basic?
Answer: 2018