marathon oil corporation notes to consolidated financial statements expected long-term return on plan assets 2013 the expected long-term return on plan assets assumption for our u.s .
funded plan is determined based on an asset rate-of-return modeling tool developed by a third-party investment group which utilizes underlying assumptions based on actual returns by asset category and inflation and takes into account our u.s .
pension plan 2019s asset allocation .
to determine the expected long-term return on plan assets assumption for our international plans , we consider the current level of expected returns on risk-free investments ( primarily government bonds ) , the historical levels of the risk premiums associated with the other applicable asset categories and the expectations for future returns of each asset class .
the expected return for each asset category is then weighted based on the actual asset allocation to develop the overall expected long-term return on plan assets assumption .
assumed weighted average health care cost trend rates .

2018
2017
2016
Initial health care trend rate
N/A
8.00%
8.25%
Ultimate trend rate
N/A
4.70%
4.50%
Year ultimate trend rate is reached
N/A
2025
2025

n/a all retiree medical subsidies are frozen as of january 1 , 2019 .
employer provided subsidies for post-65 retiree health care coverage were frozen effective january 1 , 2017 at january 1 , 2016 established amount levels .
company contributions are funded to a health reimbursement account on the retiree 2019s behalf to subsidize the retiree 2019s cost of obtaining health care benefits through a private exchange ( the 201cpost-65 retiree health benefits 201d ) .
therefore , a 1% ( 1 % ) change in health care cost trend rates would not have a material impact on either the service and interest cost components and the postretirement benefit obligations .
in the fourth quarter of 2018 , we terminated the post-65 retiree health benefits effective as of december 31 , 2020 .
the post-65 retiree health benefits will no longer be provided after that date .
in addition , the pre-65 retiree medical coverage subsidy has been frozen as of january 1 , 2019 , and the ability for retirees to opt in and out of this coverage , as well as pre-65 retiree dental and vision coverage , has also been eliminated .
retirees must enroll in connection with retirement for such coverage , or they lose eligibility .
these plan changes reduced our retiree medical benefit obligation by approximately $ 99 million .
plan investment policies and strategies 2013 the investment policies for our u.s .
and international pension plan assets reflect the funded status of the plans and expectations regarding our future ability to make further contributions .
long-term investment goals are to : ( 1 ) manage the assets in accordance with applicable legal requirements ; ( 2 ) produce investment returns which meet or exceed the rates of return achievable in the capital markets while maintaining the risk parameters set by the plan's investment committees and protecting the assets from any erosion of purchasing power ; and ( 3 ) position the portfolios with a long-term risk/ return orientation .
investment performance and risk is measured and monitored on an ongoing basis through quarterly investment meetings and periodic asset and liability studies .
u.s .
plan 2013 the plan 2019s current targeted asset allocation is comprised of 55% ( 55 % ) equity securities and 45% ( 45 % ) other fixed income securities .
over time , as the plan 2019s funded ratio ( as defined by the investment policy ) improves , in order to reduce volatility in returns and to better match the plan 2019s liabilities , the allocation to equity securities will decrease while the amount allocated to fixed income securities will increase .
the plan's assets are managed by a third-party investment manager .
international plan 2013 our international plan's target asset allocation is comprised of 55% ( 55 % ) equity securities and 45% ( 45 % ) fixed income securities .
the plan assets are invested in ten separate portfolios , mainly pooled fund vehicles , managed by several professional investment managers whose performance is measured independently by a third-party asset servicing consulting fair value measurements 2013 plan assets are measured at fair value .
the following provides a description of the valuation techniques employed for each major plan asset class at december 31 , 2018 and 2017 .
cash and cash equivalents 2013 cash and cash equivalents are valued using a market approach and are considered level 1 .
equity securities 2013 investments in common stock are valued using a market approach at the closing price reported in an active market and are therefore considered level 1 .
private equity investments include interests in limited partnerships which are valued based on the sum of the estimated fair values of the investments held by each partnership , determined using a combination of market , income and cost approaches , plus working capital , adjusted for liabilities , currency translation and estimated performance incentives .
these private equity investments are considered level 3 .
investments in pooled funds are valued using a market approach , these various funds consist of equity with underlying investments held in u.s .
and non-u.s .
securities .
the pooled funds are benchmarked against a relative public index and are considered level 2. .

Question: Analyse this data from a financial earnings document. what was the difference in the initial health care trend rate and the ultimate trend rate in 2016?
Choices:
0.0037
0.0031
0.0375
-200.9175
1.955
Correct choice index: 2