Leveraged Performance Units During the year ended May 31, 2015, certain executives were granted performance units that we refer to as “leveraged performance units,” or “LPUs.
” LPUs contain a market condition based on our relative stock price growth over a three-year performance period.
The LPUs contain a minimum threshold performance which, if not met, would result in no payout.
The LPUs also contain a maximum award opportunity set as a fixed dollar and fixed number of shares.
After the three-year performance period, which concluded in October 2017, one-third of the earned units converted to unrestricted common stock.
The remaining two-thirds converted to restricted stock that will vest in equal installments on each of the first two anniversaries of the conversion date.
We recognize share-based compensation expense based on the grant date fair value of the LPUs, as determined by use of a Monte Carlo model, on a straight-line basis over the requisite service period for each separately vesting portion of the LPU award.
The following table summarizes the changes in unvested restricted stock and performance awards for the year ended December 31, 2017, the 2016 fiscal transition period and for the years ended May 31, 2016 and 2015:
## Table 0 ##
The total fair value of restricted stock and performance awards vested was $33.7 million for the year ended December 31, 2017, $20.0 million for the 2016 fiscal transition period and $17.4 million and $15.0 million, respectively, for the years ended May 31, 2016 and 2015.
For restricted stock and performance awards, we recognized compensation expense of $35.2 million for the year ended December 31, 2017, $17.2 million for the 2016 fiscal transition period and $28.8 million and $19.8 million, respectively, for the years ended May 31, 2016 and 2015.
As of December 31, 2017, there was $46.1 million of unrecognized compensation expense related to unvested restricted stock and performance awards that we expect to recognize over a weighted-average period of 1.8 years.
Our restricted stock and performance award plans provide for accelerated vesting under certain conditions.
Stock Options Stock options are granted with an exercise price equal to 100% of fair market value of our common stock on the date of grant and have a term of ten years.
Stock options granted before the year ended May 31, 2015 vest in equal installments on each of the first four anniversaries of the grant date.
Stock options granted during the year ended May 31, 2015 and thereafter vest in equal installments on each of the first three anniversaries of the grant date.
Our stock option plans provide for accelerated vesting under certain conditions.
(1) The roll forward of the benefit obligation and the roll forward of plan assets have not been restated for discontinued operations for 2015 as it is impractical to do so.
(2) At December 31, 2016, the benefit obligation, fair value of plan assets, and funded status for U. S.  pension plans were $5,707, $3,495, and $(2,212), respectively.
At December 31, 2015, the benefit obligation, fair value of plan assets, and funded status for U. S.  pension plans were $10,983, $8,077, and $(2,906), respectively.
Pension Plan Benefit Obligations
## Table 1 ##
Components of Net Periodic Benefit Cost
## Table 2 ##
Note: the footnotes below include components of Net Periodic Benefit Cost related to Alcoa Corporation through the completion of the Separation Transaction.
(1) In 2016, 2015, and 2014, net periodic benefit cost for U.
S pension plans was $261, $423, and $335, respectively.
(2) In 2016, 2015, and 2014, net periodic benefit cost for other postretirement benefits reflects a reduction of $22, $34, and $38, respectively, related to the recognition of the federal subsidy awarded under Medicare Part D.  (3) In 2016, settlements were due to workforce reductions (see Note D) and the payment of lump sum benefits and/or purchases of annuity contracts.
In 2015, settlements were due to workforce reductions (see Note D) and the payment of lump sum benefits and/or purchases of annuity contracts.
In 2014, settlements were due to workforce reductions (see Note D).
(4) In 2015, curtailments were due to elimination of benefits or workforce reductions (see Note D).
(5) In 2016 and 2015, special termination benefits were due to workforce reductions (see Note D).
(6) Amounts attributed to joint venture partners are not included
* As of December 31, 2016, the total fair value of pension plans’ assets excludes a net receivable of $20, which represents assets due from the Alcoa Corporation as a result of plan separations and securities sold not yet settled plus interest and dividends earned on various investments.
**As of December 31, 2015, the total fair value of pension plans’ assets excludes a net receivable of $2 which represents securities sold not yet settled plus interest and dividends earned on various investments.
Funding and Cash Flows It is Arconic’s policy to fund amounts for pension plans sufficient to meet the minimum requirements set forth in applicable country benefits laws and tax laws, including the Pension Protection Act of 2006; the Worker, Retiree, and Employer Recovery Act of 2008; the Moving Ahead for Progress in the 21st Century Act of 2012; the Highway and Transportation Funding Act of 2014; and the Bipartisan Budget Act of 2015 for U. S.  plans.
From time to time, Arconic contributes additional amounts as deemed appropriate.
In 2016 and 2015, cash contributions to Arconic’s pension plans were $290 and $470.
The minimum required contribution to pension plans in 2017 is estimated to be $310, of which $290 is for U. S.  plans.
During the third quarter of 2016, the Pension Benefit Guaranty Corporation approved management’s plan to separate the Alcoa Inc.  pension plans between Arconic and Alcoa Corporation in connection with the Separation Transaction.
The plan stipulates that Arconic will make cash contributions totaling $150 over a period of 30 months to its two largest pension plans.
The payments are expected to be made in increments no less than $50 each over the 30-month period, with the first payment due no later than six months after the separation date of November 1, 2016.
Benefit payments expected to be paid to pension and other postretirement benefit plans’ participants and expected Medicare Part D subsidy receipts are as follows utilizing the current assumptions outlined above:
## Table 3 ##
Defined Contribution Plans Arconic sponsors savings and investment plans in various countries, primarily in the United States.
Expenses related to these plans were $71 in 2016, $83 in 2015, and $83 in 2014.
In the United States, employees may contribute a portion of their compensation to the plans, and Arconic matches a portion of these contributions in equivalent form of the investments elected by the employee.
V.  Other Financial Instruments Fair Value.
Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date.
The fair value hierarchy distinguishes between (i) market participant assumptions developed based on market data obtained from independent sources (observable inputs) and (ii) an entity’s own assumptions about market participant assumptions developed based on the best information available in the circumstances (unobservable inputs).
The fair value hierarchy consists of three broad levels, which gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities
Cost of Goods Sold (COGS)—COGS as a percentage of Sales was 79.2% in 2016 compared with 81.4% in 2015.
The primary drivers in the improvement in COGS as a percentage of sales were productivity gains across all segments and higher volume in the Engineered Products and Solutions segment due to the benefit of a full-year effect of two 2015 acquisitions.
This benefit was somewhat offset by overall cost increases across all segments and unfavorable pricing and product mix impacts primarily in the Engineered Products and Solutions and Global Rolled Products segments.
COGS as a percentage of Sales was 81.4% in 2015 compared with 82.5% in 2014.
The percentage was favorably impacted by net productivity improvements and higher volume across all segments and a favorable LIFO (last in, first out) adjustment due to lower prices for aluminum in the Global Rolled Products segment.
These positive impacts were partially offset by unfavorable price and product mix across all segments and higher costs.
Selling, General Administrative, and Other Expenses (SG&A) — SG&A expenses were $942, or 7.6% of Sales, in 2016 compared with $765, or 6.2% of Sales, in 2015.
The increase in SG&A was primarily due to costs related to the Separation Transaction of $193 in 2016, an increase of $169 from 2015 separation costs.
SG&A expenses were $765, or 6.2% of Sales, in 2015 compared with $770, or 6.1% of Sales, in 2014.
The relatively flat expense was principally the result of favorable foreign currency movements due to a stronger U. S.  dollar, the absence of SG&A related to closed and sold locations, and lower acquisition costs ($15), primarily offset by expenses for professional and consulting services related to the Separation Transaction ($24) and SG&A related to inorganic growth in the Engineered Products and Solutions segment.
Research and Development Expenses (R&D)—R&D expenses were $132 in 2016 compared with $169 in 2015 and $123 in 2014.
The decrease in 2016 as compared to 2015 was driven by the decrease in spending for the Micromill?
in San Antonio, TX which was completed in 2015 and began production of automotive sheet, on a limited basis, for the Global Rolled Products segment.
The increase in 2015 as compared to 2014 was mainly driven by additional spending related to the upgrade of the Micromill?.
Provision for Depreciation and Amortization (D&A)—The provision for D&A was $535 in 2016 compared with $508 in 2015.
The increase of $27, or 5.3%, related to a full year of D&A related to two acquisitions which occurred during 2015 (see Engineered Products and Solutions in Segment Information below).
The provision for D&A was $508 in 2015 compared with $436 in 2014.
The increase of $72, or 16.5%, related primarily to new D&A ($93) associated with three acquisitions that occurred from November 2014 through July 2015 (see Engineered Products and Solutions in Segment Information below).
This increase was partially offset by the absence of D&A related to the divestiture and/or permanent closure of six rolling mills (see Global Rolled Products in Segment Information below).
Impairment of Goodwill—In 2015, Arconic recognized an impairment of goodwill in the amount of $25, related to the annual impairment review of the soft alloy extrusion business in Brazil (see Goodwill in Critical Accounting Policies and Estimates below).
Restructuring and Other Charges—Restructuring and other charges for each year in the three-year period ended December 31, 2016 were comprised of the following:
## Table 4 ##
Solutions segment, 45 in the Global Rolled Products segment, and 110 in Corporate); a net charge of $10 ($7 after-tax) for other miscellaneous items; and $10 ($5 after-tax) for the reversal of a number of layoff reserves related to prior periods.
In early 2014, management approved the permanent shutdown of Arconic’s two rolling mills in Australia, Point Henry and Yennora.
This decision was made due to the significant impact of excess can sheet capacity in both Australia and Asia.
The two rolling mills had a combined can sheet capacity of 200,000 metric-tons-per-year and were closed by the end of 2014.
Costs related to the shutdown of the two rolling mills included $56 for the separation of approximately 470 employees; accelerated depreciation of $58 as the rolling mills continued to operate during 2014; asset impairments of $7 representing the write-off of the remaining book value of all related properties, plants, and equipment; and $33 in other exit costs.
Additionally, in 2014, remaining inventories, mostly operating supplies and raw materials, were written down to their net realizable value, resulting in a charge of $13 ($9 after-tax), which was recorded in Cost of goods sold on the accompanying Statement of Consolidated Operations.
The other exit costs of $33 represent $18 in environmental remediation and $8 in asset retirement obligations, both of which were triggered by the decisions to permanently shut down and demolish the aforementioned structures in Australia, and $7 in other related costs, including supplier and customer contract-related costs.
Demolition and remediation activities related to the two rolling mills began in mid-2015 and are expected to be completed by the end of 2018.
As of December 31, 2016, the separations associated with 2014 restructuring programs were essentially complete.
In 2016, 2015, and 2014, cash payments of $3, $27, and $54, respectively, were made against layoff reserves related to 2014 restructuring programs.
Arconic does not include Restructuring and other charges in the results of its reportable segments.
The pretax impact of allocating such charges to segment results would have been as follows:

<table><tr><td></td><td>Shares (in thousands)</td><td>Weighted-AverageGrant-DateFair Value</td></tr><tr><td>Unvested at May 31, 2014</td><td>1,754</td><td>$22.72</td></tr><tr><td>Granted</td><td>954</td><td>36.21</td></tr><tr><td>Vested</td><td>-648</td><td>23.17</td></tr><tr><td>Forfeited</td><td>-212</td><td>27.03</td></tr><tr><td>Unvested at May 31, 2015</td><td>1,848</td><td>28.97</td></tr><tr><td>Granted</td><td>461</td><td>57.04</td></tr><tr><td>Vested</td><td>-633</td><td>27.55</td></tr><tr><td>Forfeited</td><td>-70</td><td>34.69</td></tr><tr><td>Unvested at May 31, 2016</td><td>1,606</td><td>37.25</td></tr><tr><td>Granted</td><td>348</td><td>74.26</td></tr><tr><td>Vested</td><td>-639</td><td>31.38</td></tr><tr><td>Forfeited</td><td>-52</td><td>45.27</td></tr><tr><td>Unvested at December 31, 2016</td><td>1,263</td><td>49.55</td></tr><tr><td>Granted</td><td>899</td><td>79.79</td></tr><tr><td>Vested</td><td>-858</td><td>39.26</td></tr><tr><td>Forfeited</td><td>-78</td><td>59.56</td></tr><tr><td>Unvested at December 31, 2017</td><td>1,226</td><td>$78.29</td></tr></table>
<table><tr><td></td><td colspan="2"> Pension benefits</td></tr><tr><td></td><td> 2016</td><td> 2015</td></tr><tr><td>The projected benefit obligation and accumulated benefit obligation for all defined benefit pension plans was asfollows:</td><td></td><td></td></tr><tr><td>Projected benefit obligation</td><td>$7,026</td><td>$14,247</td></tr><tr><td>Accumulated benefit obligation</td><td>6,850</td><td>13,832</td></tr><tr><td>The aggregate projected benefit obligation and fair value of plan assets for pension plans with projected benefit obligations inexcess of plan assets was as follows:</td><td></td><td></td></tr><tr><td>Projected benefit obligation</td><td>6,995</td><td>14,146</td></tr><tr><td>Fair value of plan assets</td><td>4,629</td><td>10,786</td></tr><tr><td>The aggregate accumulated benefit obligation and fair value of plan assets for pension plans with accumulated benefit obligationsin excess of plan assets was as follows:</td><td></td><td></td></tr><tr><td>Accumulated benefit obligation</td><td>6,104</td><td>12,510</td></tr><tr><td>Fair value of plan assets</td><td>3,894</td><td>9,512</td></tr></table>
<table><tr><td></td><td colspan="3">Pension benefits -1</td><td colspan="3">Other postretirement benefits -2</td></tr><tr><td></td><td>2016</td><td>2015</td><td>2014</td><td>2016</td><td>2015</td><td>2014</td></tr><tr><td>Service cost</td><td>$155</td><td>$175</td><td>$166</td><td>$13</td><td>$14</td><td>$15</td></tr><tr><td>Interest cost</td><td>431</td><td>577</td><td>630</td><td>63</td><td>92</td><td>114</td></tr><tr><td>Expected return on plan assets</td><td>-677</td><td>-753</td><td>-782</td><td>-</td><td>-</td><td>-</td></tr><tr><td>Recognized net actuarial loss</td><td>380</td><td>468</td><td>391</td><td>24</td><td>17</td><td>13</td></tr><tr><td>Amortization of prior service cost (benefit)</td><td>13</td><td>16</td><td>18</td><td>-24</td><td>-37</td><td>-25</td></tr><tr><td>Settlements<sup>-3</sup></td><td>19</td><td>16</td><td>26</td><td>-</td><td>-</td><td>-</td></tr><tr><td>Curtailments<sup>-4</sup></td><td>-</td><td>9</td><td>-</td><td>-</td><td>-4</td><td>-</td></tr><tr><td>Special termination benefits<sup>-5</sup></td><td>2</td><td>16</td><td>-</td><td>-</td><td>-</td><td>-</td></tr><tr><td>Net periodic benefit cost<sup>-6</sup></td><td>$323</td><td>$524</td><td>$449</td><td>$76</td><td>$82</td><td>$117</td></tr><tr><td>Discontinued operations</td><td>122</td><td>248</td><td>215</td><td>41</td><td>43</td><td>68</td></tr><tr><td>Net amount recognized in Statement of Consolidated Operations</td><td>$201</td><td>$276</td><td>$234</td><td>$35</td><td>$39</td><td>$49</td></tr></table>
<table><tr><td> Year ended December 31,</td><td> Pension benefits</td><td> Gross Other post- retirement benefits</td><td> Medicare Part D subsidy receipts</td><td> Net Other post- retirement benefits</td></tr><tr><td>2017</td><td>$420</td><td>$95</td><td>$5</td><td>$90</td></tr><tr><td>2018</td><td>425</td><td>95</td><td>5</td><td>90</td></tr><tr><td>2019</td><td>425</td><td>95</td><td>5</td><td>90</td></tr><tr><td>2020</td><td>430</td><td>95</td><td>5</td><td>90</td></tr><tr><td>2021</td><td>435</td><td>95</td><td>5</td><td>90</td></tr><tr><td>2022 through 2026</td><td>2,195</td><td>415</td><td>35</td><td>380</td></tr><tr><td></td><td>$4,330</td><td>$890</td><td>$60</td><td>$830</td></tr></table>
<table><tr><td></td><td>2016</td><td>2015</td><td>2014</td></tr><tr><td>Asset impairments</td><td>$80</td><td>$-</td><td>$65</td></tr><tr><td>Layoff costs</td><td>70</td><td>97</td><td>105</td></tr><tr><td>Net loss on divestitures of businesses</td><td>3</td><td>136</td><td>111</td></tr><tr><td>Other</td><td>27</td><td>-11</td><td>43</td></tr><tr><td>Reversals of previously recorded layoff costs</td><td>-25</td><td>-8</td><td>-10</td></tr><tr><td>Restructuring and other charges</td><td>$155</td><td>$214</td><td>$314</td></tr></table>

Question: what was the change in millions in the total fair value of restricted stock and performance awards vested from 2016 to 2017?
Answer: 13.7