( 2 ) in 2013 , our principal u.k subsidiary agreed with the trustees of one of the u.k .
plans to contribute an average of $ 11 million per year to that pension plan for the next three years .
the trustees of the plan have certain rights to request that our u.k .
subsidiary advance an amount equal to an actuarially determined winding-up deficit .
as of december 31 , 2015 , the estimated winding-up deficit was a3240 million ( $ 360 million at december 31 , 2015 exchange rates ) .
the trustees of the plan have accepted in practice the agreed-upon schedule of contributions detailed above and have not requested the winding-up deficit be paid .
( 3 ) purchase obligations are defined as agreements to purchase goods and services that are enforceable and legally binding on us , and that specifies all significant terms , including what is to be purchased , at what price and the approximate timing of the transaction .
most of our purchase obligations are related to purchases of information technology services or other service contracts .
( 4 ) excludes $ 12 million of unfunded commitments related to an investment in a limited partnership due to our inability to reasonably estimate the period ( s ) when the limited partnership will request funding .
( 5 ) excludes $ 218 million of liabilities for uncertain tax positions due to our inability to reasonably estimate the period ( s ) when potential cash settlements will be made .
financial condition at december 31 , 2015 , our net assets were $ 6.2 billion , representing total assets minus total liabilities , a decrease from $ 6.6 billion at december 31 , 2014 .
the decrease was due primarily to share repurchases of $ 1.6 billion , dividends of $ 323 million , and an increase in accumulated other comprehensive loss of $ 289 million related primarily to an increase in the post- retirement benefit obligation , partially offset by net income of $ 1.4 billion for the year ended december 31 , 2015 .
working capital increased by $ 77 million from $ 809 million at december 31 , 2014 to $ 886 million at december 31 , 2015 .
accumulated other comprehensive loss increased $ 289 million at december 31 , 2015 as compared to december 31 , 2014 , which was primarily driven by the following : 2022 negative net foreign currency translation adjustments of $ 436 million , which are attributable to the strengthening of the u.s .
dollar against certain foreign currencies , 2022 a decrease of $ 155 million in net post-retirement benefit obligations , and 2022 net financial instrument losses of $ 8 million .
review by segment general we serve clients through the following segments : 2022 risk solutions acts as an advisor and insurance and reinsurance broker , helping clients manage their risks , via consultation , as well as negotiation and placement of insurance risk with insurance carriers through our global distribution network .
2022 hr solutions partners with organizations to solve their most complex benefits , talent and related financial challenges , and improve business performance by designing , implementing , communicating and administering a wide range of human capital , retirement , investment management , health care , compensation and talent management strategies .
risk solutions .

Years ended December 31(millions, except percentage data)
2015
2014
2013
Revenue
$7,426
$7,834
$7,789
Operating income
1,506
1,648
1,540
Operating margin
20.3%
21.0%
19.8%

the demand for property and casualty insurance generally rises as the overall level of economic activity increases and generally falls as such activity decreases , affecting both the commissions and fees generated by our brokerage business .
the economic activity that impacts property and casualty insurance is described as exposure units , and is most closely correlated .

Question: Analyse this data from a financial earnings document. what is the net income margin for 2015?
Choices:
0.15252
0.16703
0.18853
134.662
-0.18853
Correct choice index: 2