ENTERGY ARKANSAS, INC.  MANAGEMENT'S FINANCIAL DISCUSSION AND ANALYSIS Results of Operations Net Income 2008 Compared to 2007 Net income decreased $92.0 million primarily due to higher other operation and maintenance expenses, higher depreciation and amortization expenses, and a higher effective income tax rate, partially offset by higher net revenue.
The higher other operation and maintenance expenses resulted primarily from the write-off of approximately $70.8 million of costs as a result of the December 2008 Arkansas Court of Appeals decision in Entergy Arkansas' base rate case.
The base rate case is discussed in more detail in Note 2 to the financial statements.2007 Compared to 2006 Net income decreased $34.0 million primarily due to higher other operation and maintenance expenses, higher depreciation and amortization expenses, and a higher effective income tax rate.
The decrease was partially offset by higher net revenue.
Net Revenue 2008 Compared to 2007 Net revenue consists of operating revenues net of: 1) fuel, fuel-related expenses, and gas purchased for resale, 2) purchased power expenses, and 3) other regulatory credits.
Following is an analysis of the change in net revenue comparing 2008 to 2007.
## Table 0 ##
The rider revenue variance is primarily due to an Energy Efficiency rider which became effective in November 2007.
The establishment of the rider results in an increase in rider revenue and a corresponding increase in other operation and maintenance expense with no effect on net income.
Also contributing to the variance was an increase in franchise tax rider revenue as a result of higher retail revenues.
The corresponding increase is in taxes other than income taxes, resulting in no effect on net income.
The purchased power capacity variance is primarily due to lower reserve equalization expenses.
The volume/weather variance is primarily due to the effect of less favorable weather on residential and commercial sales during the billed and unbilled sales periods compared to 2007 and a 2.9% volume decrease in industrial sales, primarily in the wood industry and the small customer class.
Billed electricity usage decreased 333 GWh in all sectors.
See "Critical Accounting Estimates" below and Note 1 to the financial statements for further discussion of the accounting for unbilled revenues.
Results of Operations
## Table 1 ##
NM Not Meaningful 2017 versus 2016 Revenue Revenue generated for 2017 was $4,707 million, an increase of $936 million, or 24.8%, compared to $3,771 million in 2016.
On a constant currency basis, revenue grew 23.9%.
This increase in revenue was primarily driven by additional revenue of $790 million from acquisitions.
There was also strong organic growth of $122 million during the year, driven primarily by North America as well as strength in the emerging markets, particularly in China and India.
Additionally, to a lesser extent, Europe contributed to this organic growth despite ongoing weakness in the United Kingdom during the year.
The following table illustrates the impact on 2017 revenue from organic growth, recent acquisitions and divestitures, and foreign currency translation in relation to revenue.
## Table 2 ##
calculating the net periodic benefit costs
## Table 3 ##
The assumed rate of future increases in the per capita cost of health care (the health care trend rate) is 8.72% for 2018, decreasing ratably to 4.50% in 2026.
An increase or decrease in the health care trend rates by one percent per year would impact the aggregate annual service and interest components by less than $1 million, and impact the benefit obligation by approximately $4 million.
Investment Policy The investment strategy for managing worldwide postretirement benefit plan assets is to seek an optimal rate of return relative to an appropriate level of risk for each plan.
Investment strategies vary by plan, depending on the specific characteristics of the plan, such as plan size and design, funded status, liability profile and legal requirements.
In general, the plans are managed closely to their strategic allocations.
On April 3, 2017 the liquid assets in two UK Plans transitioned into a new fund structure.
The restructuring involved transferring a portion of the assets into pooled diversified growth funds, while some investments were sold off and some were kept in place.
The pooled funds make up 64% of the assets of the two UK Plans.
Liability hedging and illiquid assets remain outside of this arrangement.
The following table provides the actual asset allocations of plan assets as of December 31, 2017 and 2016, and the related asset target allocation ranges by asset category.

<table><tr><td></td><td>Amount (In Millions)</td></tr><tr><td>2007 net revenue</td><td>$1,110.6</td></tr><tr><td>Rider revenue</td><td>13.6</td></tr><tr><td>Purchased power capacity</td><td>4.8</td></tr><tr><td>Volume/weather</td><td>-14.6</td></tr><tr><td>Other</td><td>3.5</td></tr><tr><td>2008 net revenue</td><td>$1,117.9</td></tr></table>
<table><tr><td>(in millions)</td><td>2017</td><td>2016</td><td>2015</td><td>2017 v. 2016</td><td>2016 v. 2015</td></tr><tr><td>Revenue</td><td>$4,707</td><td>$3,771</td><td>$3,653</td><td>24.8%</td><td>3.2%</td></tr><tr><td>Gross profit</td><td>1,851</td><td>1,461</td><td>1,404</td><td>26.7%</td><td>4.1%</td></tr><tr><td>Gross margin</td><td>39.3%</td><td>38.7%</td><td>38.4%</td><td>60bp</td><td>30bp</td></tr><tr><td>Total operating expenses</td><td>1,295</td><td>1,055</td><td>955</td><td>22.7%</td><td>10.5%</td></tr><tr><td>Expense to revenue ratio</td><td>27.5%</td><td>28.0%</td><td>26.1%</td><td>-50bp</td><td>190bp</td></tr><tr><td>Restructuring and realignment costs</td><td>-41</td><td>-47</td><td>-20</td><td>-12.8%</td><td>135.0%</td></tr><tr><td>Sensus acquisition related charges</td><td>-22</td><td>-53</td><td>—</td><td>-58.5%</td><td>NM</td></tr><tr><td>Special charges</td><td>-11</td><td>-5</td><td>-5</td><td>120.0%</td><td>—%</td></tr><tr><td>Operating expenses excluding restructuring and realignment costs, Sensus acquisition related costs and special charges</td><td>1,221</td><td>950</td><td>930</td><td>28.5%</td><td>2.2%</td></tr><tr><td>Expense to revenue ratio</td><td>25.9%</td><td>25.2%</td><td>25.5%</td><td>70bp</td><td>-30bp</td></tr><tr><td>Operating income</td><td>556</td><td>406</td><td>449</td><td>36.9%</td><td>-9.6%</td></tr><tr><td>Operating margin</td><td>11.8%</td><td>10.8%</td><td>12.3%</td><td>100bp</td><td>-150bp</td></tr><tr><td>Interest and other non-operating expense (income), net</td><td>80</td><td>66</td><td>55</td><td>21.2%</td><td>20.0%</td></tr><tr><td>(Loss)/gain from sale of businesses</td><td>-10</td><td>—</td><td>9</td><td>NM</td><td>NM</td></tr><tr><td>Income tax expense</td><td>136</td><td>80</td><td>63</td><td>70.0%</td><td>27.0%</td></tr><tr><td>Tax rate</td><td>29.2%</td><td>23.5%</td><td>15.6%</td><td>570bp</td><td>790bp</td></tr><tr><td>Net income</td><td>$330</td><td>$260</td><td>$340</td><td>26.9%</td><td>-23.5%</td></tr></table>
<table><tr><td></td><td colspan="2">Water Infrastructure</td><td colspan="2">Applied Water</td><td colspan="2">Measurement & Control Solutions</td><td colspan="2">Total Xylem</td></tr><tr><td>(in millions)</td><td>$ Change</td><td>% Change</td><td>$ Change</td><td>% Change</td><td>$ Change</td><td>% Change</td><td>$ Change</td><td>% Change</td></tr><tr><td>2016 Revenue</td><td>$1,932</td><td></td><td>$1,393</td><td></td><td>$446</td><td></td><td>$3,771</td><td></td></tr><tr><td>Organic Growth</td><td>56</td><td>2.9%</td><td>34</td><td>2.4%</td><td>32</td><td>7.2%</td><td>122</td><td>3.2%</td></tr><tr><td>Acquisitions/(Divestitures)</td><td>—</td><td>—%</td><td>-10</td><td>-0.7%</td><td>790</td><td>177.1%</td><td>780</td><td>20.7%</td></tr><tr><td>Constant Currency</td><td>56</td><td>2.9%</td><td>24</td><td>1.7%</td><td>822</td><td>184.3%</td><td>902</td><td>23.9%</td></tr><tr><td>Foreign currency translation (a)</td><td>16</td><td>0.8%</td><td>4</td><td>0.3%</td><td>14</td><td>3.1%</td><td>34</td><td>0.9%</td></tr><tr><td>Total change in revenue</td><td>72</td><td>3.7%</td><td>28</td><td>2.0%</td><td>836</td><td>187.4%</td><td>936</td><td>24.8%</td></tr><tr><td>2017 Revenue</td><td>$2,004</td><td></td><td>$1,421</td><td></td><td>$1,282</td><td></td><td>$4,707</td><td></td></tr></table>
<table><tr><td></td><td>2017</td><td>2016</td><td>2015</td></tr><tr><td>Expected long-term rate of return on plan assets</td><td>7.30%</td><td>7.32%</td><td>7.38%</td></tr><tr><td>Actual rate of return on plan assets</td><td>5.70%</td><td>12.20%</td><td>3.51%</td></tr></table>

Question: In the year with lowest amount of Operating income, what's the increasing rate of Income tax expense? (in %)
Answer: 0.7