5.
Stock Based Compensation Overview MAA accounts for its stock based employee compensation plans in accordance with accounting standards governing stock based compensation.
These standards require an entity to measure the cost of employee services received in exchange for an award of an equity instrument based on the award's fair value on the grant date and recognize the cost over the period during which the employee is required to provide service in exchange for the award, which is generally the vesting period.
Any liability awards issued are remeasured at each reporting period.
MAA’s stock compensation plans consist of a number of incentives provided to attract and retain independent directors, executive officers and key employees.
Incentives are currently granted under the Second Amended and Restated 2013 Stock Incentive Plan, or the Stock Plan, which was approved at the 2018 annual meeting of MAA shareholders.
The Stock Plan allows for the grant of restricted stock and stock options up to 2,000,000 shares.
MAA believes that such awards better align the interests of its employees with those of its shareholders.
Compensation expense is generally recognized for service based restricted stock awards using the straight-line method over the vesting period of the shares regardless of cliff or ratable vesting distinctions.
Compensation expense for market and performance based restricted stock awards is generally recognized using the accelerated amortization method with each vesting tranche valued as a separate award, with a separate vesting date, consistent with the estimated value of the award at each period end.
Additionally, compensation expense is adjusted for actual forfeitures for all awards in the period that the award was forfeited.
Compensation expense for stock options is generally recognized on a straight-line basis over the requisite service period.
MAA presents stock compensation expense in the Consolidated Statements of Operations in "General and administrative expenses".
Total compensation expense under the Stock Plan was $12.9 million, $10.8 million and $12.2 million for the years ended December 31, 2018, 2017 and 2016, respectively.
Of these amounts, total compensation expense capitalized was $0.5 million, $0.2 million and $0.7 million for the years ended December 31, 2018, 2017 and 2016, respectively.
As of December 31, 2018, the total unrecognized compensation expense was $13.5 million.
This cost is expected to be recognized over the remaining weighted average period of 1.1 years.
Total cash paid for the settlement of plan shares totaled $2.9 million, $4.8 million and $2.0 million for the years ended December 31, 2018, 2017 and 2016, respectively.
Information concerning grants under the Stock Plan is provided below.
Restricted Stock In general, restricted stock is earned based on either a service condition, performance condition, or market condition, or a combination thereof, and generally vests ratably over a period from 1 year to 5 years.
Service based awards are earned when the employee remains employed over the requisite service period and are valued on the grant date based upon the market price of MAA common stock on the date of grant.
Market based awards are earned when MAA reaches a specified stock price or specified return on the stock price (price appreciation plus dividends) and are valued on the grant date using a Monte Carlo simulation.
Performance based awards are earned when MAA reaches certain operational goals such as funds from operations, or FFO, targets and are valued based upon the market price of MAA common stock on the date of grant as well as the probability of reaching the stated targets.
MAA remeasures the fair value of the performance based awards each balance sheet date with adjustments made on a cumulative basis until the award is settled and the final compensation is known.
The weighted average grant date fair value per share of restricted stock awards granted during the years ended December 31, 2018, 2017 and 2016, was $71.85, $84.53 and $73.20, respectively.
The following is a summary of the key assumptions used in the valuation calculations for market based awards granted during the years ended December 31, 2018, 2017 and 2016:
## Table 0 ##
The risk free rate was based on a zero coupon risk-free rate.
The minimum risk free rate was based on a period of 0.25 years for the years ended December 31, 2018, 2017 and 2016.
The maximum risk free rate was based on a period of 3 years for the years ended December 31, 2018, 2017 and 2016.
The dividend yield was based on the closing stock price of MAA stock on the
## Table 1 ##
Sales and marketing expenses consist primarily of personnel-related costs, including salaries, commissions, benefits and stock-based compensation for our employees engaged in sales, sales support, business development and media, marketing, corporate communications and customer service functions.
In addition, marketing and sales-related expenses also include market research, tradeshows, branding, marketing, public relations costs, amortization of acquired intangible assets, as well as allocated facilities and other supporting overhead costs.2014 Compared to 2013.
In 2014, sales and marketing expenses increased by $297.9 million compared to 2013.
The increase was primarily attributable to a $153.2 million increase in personnel-related costs, mainly driven by an increase in average employee headcount, a $98.8 million increase in marketing and sales-related expenses, a $38.1 million increase in allocated facilities and other supporting overhead expenses due to the continued expansion of our real estate footprint and increase in support functions, and a $7.8 million increase in amortization of acquired intangible assets.2013 Compared to 2012.
In 2013, sales and marketing expenses increased by $229.7 million compared to 2012.
The increase was primarily attributable to a $176.2 million increase in personnel-related costs, mainly driven by an increase in average employee headcount and recognition of stock-based compensation expense triggered by our initial public offering, a $32.9 million increase in marketing and sales-related expenses and a $20.6 million increase in allocated facilities and other supporting overhead expenses due to the continued expansion of our real estate footprint and increase in support functions.
We plan to continue to invest in sales and marketing to expand internationally, grow our advertiser base and increase our brand awareness.
We expect that sales and marketing expenses will increase in absolute dollar amounts for the foreseeable future and vary in the near term from period to period as a percentage of revenue.
General and Administrative
## Table 2 ##
General and administrative expenses consist primarily of personnel-related costs, including salaries, benefits and stock-based compensation, for our executive, finance, legal, information technology, human resources and other administrative employees.
In addition, general and administrative expenses include fees and costs for professional services, including consulting, third-party legal and accounting services and facilities and other supporting overhead costs that are not allocated to other departments.2014 Compared to 2013.
In 2014, general and administrative expense increased by $66.1 million compared to 2013.
The increase was primarily attributable to a $51.3 million increase in personnel-related costs, mainly driven by an increase in average employee headcount and recognition of stock-based compensation expense, an increase of $16.3 million in fees and costs for professional services, partially offset by a $1.5 million decrease in unallocated facilities and supporting costs, driven by slower headcount growth in the general and administrative function relative to other functional areas.2013 Compared to 2012.
In 2013, general and administrative expense increased by $64.1 million compared to 2012.
The increase was primarily attributable to a $69.2 million increase in personnel-related costs, mainly driven by an increase in average employee headcount and recognition of stock-based compensation expense triggered by our initial public offering, an increase of $10.7 million in fees and costs for professional services, partially offset by a $15.8 million decrease in unallocated facilities and supporting costs, driven by slower headcount growth in the general and administrative function relative to other functional areas.
Provision (benefit) for income taxes consists of federal and state income taxes in the United States and income taxes in certain foreign jurisdictions, and deferred income taxes and changes in related valuation allowance reflecting the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes.2014 Compared to 2013.
Our benefit for income taxes in 2014 decreased by $1.3 million compared to a benefit of $1.8 million in 2013.
The decrease was primarily due to the increased income tax expense in foreign jurisdictions, partially offset by the increased income tax benefit arising from acquisitions.2013 Compared to 2012.
Our benefit for income taxes in 2013 increased by $2.0 million compared to a provision of $0.2 million in 2012.
The increase was primarily due to the increased income tax benefit arising from acquisitions, partially offset by the increase in income tax expenses in foreign and state jurisdictions.
As of December 31, 2014, we had $2.60 billion of federal and $1.00 billion of state net operating loss carryforwards available to reduce future taxable income.
These net operating loss carryforwards will begin to expire for federal income tax purposes and state income tax purposes in 2027 and 2015, respectively.
We also have research credit carryforwards of $175.9 million and $142.0 million for federal and state income tax purposes, respectively.
The federal research credit carryforward will begin to expire in 2027.
The state research credit carryforward has no expiration date.
Additionally, we have California Enterprise Zone credit carryforwards of $15.9 million which will begin to expire in 2023.
Utilization of the net operating loss carryforwards and research credit carryforwards may be subject to an annual limitation due to the ownership change limitations provided by the Internal Revenue Code of 1986, as amended, and similar state provisions.
Any annual limitation may result in the expiration of net operating losses and research credits before utilization.
Quarterly Results of Operations The following table sets forth our unaudited consolidated statement of operations data for each of the eight quarters in the period ended December 31, 2014.
The unaudited quarterly statement of operations data set forth below have been prepared on a basis consistent with our audited annual consolidated financial statements in this Annual Report on Form 10-K and include, in our opinion, all normal recurring adjustments necessary for a fair statement of the financial information contained in those statements.
Our historical results are not necessarily indicative of the results that may be expected in the future.
The following quarterly financial data should be read in conjunction with our audited consolidated financial statements and the related notes included elsewhere in this Annual Report on Form 10-K.
## Table 3 ##
Operating expense, excluding the impact of stock-based compensation expense, increased in every quarter presented primarily due to the continued expansion of our facilities and an increase in average employee headcount.
In addition, we experienced a varied level of capitalization of research and development expense as a result of the development of software programs and websites for internal use, due to the timing and extent of projects eligible for capitalization.
Cost of revenue and operating expenses include significant amounts of stock-based compensation expense.
Prior to the closing of our initial public offering in November 2013, we had not recognized any stock-based compensation expense for the Pre-2013 RSUs, because the performance condition had not been satisfied.
Upon completion of our initial public offering, we began recording the stock-based compensation expense related to Pre-2013 RSUs, because the satisfaction of the performance condition became probable.
During the year ended December 31, 2013, the amount of stock-based compensation expense recorded in relation to Pre-2013 RSUs totaled approximately $433.5 million.
This amount is comprised of $405.9 million of expense accumulated until the effective date of our initial public offering for awards vested and $27.6 million of subsequent recognition of expense during the year as additional Pre-2013 RSUs continue to vest.
Credit Facility In October 2013, we entered into a revolving credit agreement with certain lenders which provides for a $1.0 billion revolving unsecured credit facility maturing on October 22, 2018.
Loans under the credit facility bear interest, at our option, at (i) a base rate based on the highest of the prime rate, the federal funds rate plus 0.50% and an adjusted LIBOR rate for a one-month interest period plus 1.00%, in each case plus a margin ranging from 0.00% to 0.75% or (ii) an adjusted LIBOR rate plus a margin ranging from 1.00% to 1.75%.
This margin is determined based on our total leverage ratio for the preceding four fiscal quarter period.
We are also obligated to pay other customary fees for a credit facility of this size and type, including an upfront fee and an unused commitment fee.
Our obligations under the credit facility are guaranteed by one of our wholly-owned subsidiaries.
In addition, the credit facility contains restrictions on payments including cash payment of dividends.
The revolving credit agreement was amended in September 2014 to increase the amount of indebtedness that we may incur and increase the amount of restricted payments that we may make.
This amendment to the revolving credit agreement also provides that if our total leverage ratio exceeds 2.5:1.0 and if the amount outstanding under the credit facility exceeds $500.0 million, or 50% of the amount that may be borrowed under the credit facility, the credit facility will become secured by substantially all of our and certain of our subsidiaries’ assets, subject to limited exceptions.
As of December 31, 2014, no amounts were drawn under the credit facility.
Liquidity and Capital Resources

<table><tr><td></td><td>2018</td><td>2017</td><td>2016</td></tr><tr><td>Risk free rate</td><td>1.61% - 2.14%</td><td>0.65% - 1.57%</td><td>0.49% - 1.27%</td></tr><tr><td>Dividend yield</td><td>3.884%</td><td>3.573%</td><td>3.634%</td></tr><tr><td>Volatility</td><td>15.05% - 17.18%</td><td>20.43% - 21.85%</td><td>18.41% - 19.45%</td></tr><tr><td>Requisite service period</td><td>3 years</td><td>3 years</td><td>3 years</td></tr></table>
<table><tr><td></td><td colspan="3">Year Ended December 31,</td><td rowspan="2">2013 to 2014 % Change</td><td rowspan="2">2012 to 2013 % Change</td></tr><tr><td></td><td>2014</td><td>2013</td><td>2012</td></tr><tr><td></td><td colspan="3">(in thousands)</td><td></td><td></td></tr><tr><td>Sales and marketing</td><td>$614,110</td><td>$316,216</td><td>$86,551</td><td>94%</td><td>265%</td></tr><tr><td>Sales and marketing as a percentage of revenue</td><td>44%</td><td>48%</td><td>27%</td><td></td><td></td></tr></table>
<table><tr><td></td><td colspan="3">Year Ended December 31,</td><td rowspan="2">2013 to 2014 % Change</td><td rowspan="2">2012 to 2013 % Change</td></tr><tr><td></td><td>2014</td><td>2013</td><td>2012</td></tr><tr><td></td><td colspan="3">(in thousands)</td><td></td><td></td></tr><tr><td>General and administrative</td><td>$189,906</td><td>$123,795</td><td>$59,693</td><td>53%</td><td>107%</td></tr><tr><td>General and administrative as a percentage of revenue</td><td>14%</td><td>19%</td><td>19%</td><td></td><td></td></tr></table>
<table><tr><td></td><td colspan="8">Three Months Ended</td></tr><tr><td></td><td>Dec. 31, 2014</td><td>Sep. 30, 2014</td><td>Jun. 30, 2014</td><td>Mar. 31, 2014</td><td>Dec. 31, 2013</td><td>Sep. 30, 2013</td><td>Jun. 30, 2013</td><td>Mar. 31, 2013</td></tr><tr><td></td><td colspan="8">(Unaudited, in thousands, except per share data)</td></tr><tr><td>Consolidated Statement of Operations Data:</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>Revenue</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>Advertising services</td><td>$432,001</td><td>$320,196</td><td>$277,440</td><td>$226,051</td><td>$219,677</td><td>$153,437</td><td>$120,972</td><td>$100,460</td></tr><tr><td>Data licensing and other</td><td>47,077</td><td>41,070</td><td>34,726</td><td>24,441</td><td>22,998</td><td>15,143</td><td>18,320</td><td>13,883</td></tr><tr><td>Total revenue</td><td>479,078</td><td>361,266</td><td>312,166</td><td>250,492</td><td>242,675</td><td>168,580</td><td>139,292</td><td>114,343</td></tr><tr><td>Costs and expenses<sup>-1</sup></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>Cost of revenue</td><td>136,613</td><td>124,166</td><td>100,027</td><td>85,503</td><td>112,651</td><td>62,239</td><td>50,573</td><td>41,255</td></tr><tr><td>Research and development</td><td>181,715</td><td>183,342</td><td>177,095</td><td>149,391</td><td>394,848</td><td>87,307</td><td>64,263</td><td>47,574</td></tr><tr><td>Sales and marketing</td><td>203,599</td><td>164,015</td><td>140,261</td><td>106,235</td><td>177,305</td><td>61,214</td><td>45,258</td><td>32,439</td></tr><tr><td>General and administrative</td><td>55,304</td><td>51,174</td><td>44,694</td><td>38,734</td><td>67,547</td><td>21,152</td><td>18,114</td><td>16,982</td></tr><tr><td>Total costs and expenses</td><td>577,231</td><td>522,697</td><td>462,077</td><td>379,863</td><td>752,351</td><td>231,912</td><td>178,208</td><td>138,250</td></tr><tr><td>Loss from operations</td><td>-98,153</td><td>-161,431</td><td>-149,911</td><td>-129,371</td><td>-509,676</td><td>-63,332</td><td>-38,916</td><td>-23,907</td></tr><tr><td>Interest income (expense), net</td><td>-23,513</td><td>-5,795</td><td>-2,110</td><td>-2,567</td><td>-2,387</td><td>-1,727</td><td>-1,513</td><td>-1,233</td></tr><tr><td>Other income (expense), net</td><td>1</td><td>-8,079</td><td>1,780</td><td>798</td><td>-2,725</td><td>818</td><td>-1,019</td><td>-1,529</td></tr><tr><td>Loss before income taxes</td><td>-121,665</td><td>-175,305</td><td>-150,241</td><td>-131,140</td><td>-514,788</td><td>-64,241</td><td>-41,448</td><td>-26,669</td></tr><tr><td>Provision (benefit) for income taxes</td><td>3,687</td><td>159</td><td>-5,599</td><td>1,222</td><td>-3,317</td><td>360</td><td>777</td><td>357</td></tr><tr><td>Net loss</td><td>$-125,352</td><td>$-175,464</td><td>$-144,642</td><td>$-132,362</td><td>$-511,471</td><td>$-64,601</td><td>$-42,225</td><td>$-27,026</td></tr><tr><td>Net loss per share attributable to common stockholders:</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>Basic and diluted</td><td>$-0.20</td><td>$-0.29</td><td>$-0.24</td><td>$-0.23</td><td>$-1.41</td><td>$-0.48</td><td>$-0.32</td><td>$-0.21</td></tr><tr><td>Other Financial Information:</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>Adjusted EBITDA<sup>-2</sup></td><td>$141,490</td><td>$68,326</td><td>$54,131</td><td>$36,949</td><td>$44,745</td><td>$9,293</td><td>$9,647</td><td>$11,745</td></tr><tr><td>Non-GAAP net income (loss)<sup>(3)</sup></td><td>$79,320</td><td>$6,972</td><td>$14,596</td><td>$183</td><td>$9,774</td><td>$-17,216</td><td>$-16,364</td><td>$-10,524</td></tr></table>

Question: what was the percent of the change in the weighted average grant date fair value per share of restricted stock awards granted from 2016 to 2017