( 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', '$ 7426', '$ 7834', '$ 7789'], ['operating income', '1506', '1648', '1540'], ['operating margin', '20.3% ( 20.3 % )', '21.0% ( 21.0 % )', '19.8% ( 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: what is the net income margin for 2015?
Answer: 18.9%