Task: Table-QA (source dataset: FinQA)

Task: 
You are given a table containing structured data and a natural language question referring to the table. Your goal is to analyze the table and provide an accurate and concise answer based on the given data.

Instructions:
1. Understand the Table: Examine the structure, headers, and data in the table. Identify relevant columns and rows related to the question.
2. Interpret the Question: Determine whether the question requires direct retrieval, aggregation, comparison, sorting, filtering, or inference.
3. Extract the Answer: Use logical reasoning and numerical operations (if necessary) to derive the correct response from the table.
4. Format the Answer: No explanation, return the answer in a structured JSON format: {"answer": <answer>}. If the question cannot be answered due to missing or ambiguous data, return a JSON response with {"answer": null}.

Table:
| Unnamed: 0                          | 2017             | 2016             | 2015             |
|:------------------------------------|:-----------------|:-----------------|:-----------------|
| initial health care trend rate      | 8.00% ( 8.00 % ) | 8.25% ( 8.25 % ) | 8.00% ( 8.00 % ) |
| ultimate trend rate                 | 4.70% ( 4.70 % ) | 4.50% ( 4.50 % ) | 4.50% ( 4.50 % ) |
| year ultimate trend rate is reached | 2025             | 2025             | 2024             |

Question:
what is the difference in the initial health care trend rate and the ultimate health care trend rate in 2017?


pre_text: 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 .
post_text: 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 .
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 .
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 , 2017 and 2016 .
cash and cash equivalents 2013 cash and cash equivalents are valued using a market approach and are considered level 1 .
this investment also includes a cash reserve account ( a collective short-term investment fund ) that is valued using an income approach and is considered level 2 .
equity securities - investments in common stock and preferred 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 .
these private equity investments are considered level 3 .
investments in pooled funds are valued using a market approach at the net asset value ( "nav" ) of units held .
the various funds consist of either an equity or fixed income investment portfolio with underlying investments held in u.s .
and non-u.s .
securities .
nearly all of the underlying investments are publicly-traded .
the majority of the pooled funds are benchmarked against a relative public index .
these are considered level 2 .
fixed income securities - fixed income securities are valued using a market approach .
u.s .
treasury notes and exchange traded funds ( "etfs" ) are valued at the closing price reported in an active market and are considered level 1 .
corporate bonds , non-u.s .
government bonds , private placements , taxable municipals , gnma/fnma pools , and yankee bonds are valued using calculated yield curves created by models that incorporate various market factors .
primarily investments are held in u.s .
and non-u.s .
corporate bonds in diverse industries and are considered level 2 .
other fixed income investments include futures contracts , real estate investment trusts , credit default , zero coupon , and interest rate swaps .
the investment in the commingled .
label: 0.033
qa: answer: 3.30%
ann_table_rows: 1
2
steps: op: minus1-1
arg1: 8.00%
arg2: 4.70%
res: 3.30%
program: subtract(8.00%, 4.70%)
gold_inds: table_1: the initial health care trend rate of 2017 is 8.00% ( 8.00 % ) ; the initial health care trend rate of 2016 is 8.25% ( 8.25 % ) ; the initial health care trend rate of 2015 is 8.00% ( 8.00 % ) ;
table_2: the ultimate trend rate of 2017 is 4.70% ( 4.70 % ) ; the ultimate trend rate of 2016 is 4.50% ( 4.50 % ) ; the ultimate trend rate of 2015 is 4.50% ( 4.50 % ) ;
exe_ans: 0.033
tfidftopn: table_3: The year ultimate trend rate is reached of 2017 is 2025 ; The year ultimate trend rate is reached of 2016 is 2025 ; The year ultimate trend rate is reached of 2015 is 2024 ;
program_re: subtract(8.00%, 4.70%)
model_input: table_1
the initial health care trend rate of 2017 is 8.00% ( 8.00 % ) ; the initial health care trend rate of 2016 is 8.25% ( 8.25 % ) ; the initial health care trend rate of 2015 is 8.00% ( 8.00 % ) ;
table_2
the ultimate trend rate of 2017 is 4.70% ( 4.70 % ) ; the ultimate trend rate of 2016 is 4.50% ( 4.50 % ) ; the ultimate trend rate of 2015 is 4.50% ( 4.50 % ) ;
text_13
u.s .