what is the growth rate in operating income from 2015 to 2016?
2016 compared with 2015 net gains on investments of $ 57 million in 2016 decreased $ 52 million from 2015 due to lower net gains in 2016 . net gains on investments in 2015 included a $ 40 million gain related to the bkca acquisition and a $ 35 million unrealized gain on a private equity investment . interest and dividend income increased $ 14 million from 2015 primarily due to higher dividend income in 2016 . 2015 compared with 2014 net gains on investments of $ 109 million in 2015 decreased $ 45 million from 2014 due to lower net gains in 2015 . net gains on investments in 2015 included a $ 40 million gain related to the bkca acquisition and a $ 35 million unrealized gain on a private equity investment . net gains on investments in 2014 included the positive impact of the monetization of a nonstrategic , opportunistic private equity investment . interest expense decreased $ 28 million from 2014 primarily due to repayments of long-term borrowings in the fourth quarter of 2014 . income tax expense .

|  | GAAP | As adjusted |
| :--- | :--- | :--- |
| (in millions) | 2016 | 2015 | 2014 | 2016 | 2015 | 2014 |
| Operating income<sup>(1)</sup> | $4,570 | $4,664 | $4,474 | $4,674 | $4,695 | $4,563 |
| Total nonoperating income (expense)<sup>(1),(2)</sup> | (108) | (69) | (49) | (108) | (70) | (56) |
| Income before income taxes<sup>(2)</sup> | $4,462 | $4,595 | $4,425 | $4,566 | $4,625 | $4,507 |
| Income tax expense | $1,290 | $1,250 | $1,131 | $1,352 | $1,312 | $1,197 |
| Effective tax rate | 28.9% | 27.2% | 25.6% | 29.6% | 28.4% | 26.6% |

( 1 ) see non-gaap financial measures for further information on and reconciliation of as adjusted items . ( 2 ) net of net income ( loss ) attributable to nci . the company 2019s tax rate is affected by tax rates in foreign jurisdictions and the relative amount of income earned in those jurisdictions , which the company expects to be fairly consistent in the near term . the significant foreign jurisdictions that have lower statutory tax rates than the u.s . federal statutory rate of 35% ( 35 % ) include the united kingdom , channel islands , ireland and canada . u.s . income taxes were not provided for certain undistributed foreign earnings intended to be indefinitely reinvested outside the united states . 2016 . income tax expense ( gaap ) reflected : 2022 a net noncash benefit of $ 30 million , primarily associated with the revaluation of certain deferred income tax liabilities ; and 2022 a benefit from $ 65 million of nonrecurring items , including the resolution of certain outstanding tax matters . the as adjusted effective tax rate of 29.6% ( 29.6 % ) for 2016 excluded the net noncash benefit of $ 30 million mentioned above , as it will not have a cash flow impact and to ensure comparability among periods presented . 2015 . income tax expense ( gaap ) reflected : 2022 a net noncash benefit of $ 54 million , primarily associated with the revaluation of certain deferred income tax liabilities ; and 2022 a benefit from $ 75 million of nonrecurring items , primarily due to the realization of losses from changes in the company 2019s organizational tax structure and the resolution of certain outstanding tax matters . the as adjusted effective tax rate of 28.4% ( 28.4 % ) for 2015 excluded the net noncash benefit of $ 54 million mentioned above , as it will not have a cash flow impact and to ensure comparability among periods presented . 2014 . income tax expense ( gaap ) reflected : 2022 a $ 94 million tax benefit , primarily due to the resolution of certain outstanding tax matters related to the acquisition of bgi , including the previously mentioned $ 50 million tax benefit ( see executive summary for more information ) ; 2022 a $ 73 million net tax benefit related to several favorable nonrecurring items ; and 2022 a net noncash benefit of $ 9 million associated with the revaluation of deferred income tax liabilities . the as adjusted effective tax rate of 26.6% ( 26.6 % ) for 2014 excluded the $ 9 million net noncash benefit as it will not have a cash flow impact and to ensure comparability among periods presented and the $ 50 million tax benefit mentioned above . the $ 50 million general and administrative expense and $ 50 million tax benefit have been excluded from as adjusted results as there is no impact on blackrock 2019s book value . balance sheet overview as adjusted balance sheet the following table presents a reconciliation of the consolidated statement of financial condition presented on a gaap basis to the consolidated statement of financial condition , excluding the impact of separate account assets and separate account collateral held under securities lending agreements ( directly related to lending separate account securities ) and separate account liabilities and separate account collateral liabilities under securities lending agreements and consolidated sponsored investment funds , including consolidated vies . the company presents the as adjusted balance sheet as additional information to enable investors to exclude certain .

income_2016 = 4570
income_2015 = 4664
growth_rate = income_2016 - income_2015
percent_growth = growth_rate / income_2015
answer = percent_growth * 100