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                    | 2016             | 2015             | 2014             |
|:------------------------------|:-----------------|:-----------------|:-----------------|
| sales                         | $ 3343.6         | $ 3693.9         | $ 4078.5         |
| operating income              | 895.2            | 808.4            | 762.6            |
| operating margin              | 26.8% ( 26.8 % ) | 21.9% ( 21.9 % ) | 18.7% ( 18.7 % ) |
| equity affiliates 2019 income | 52.7             | 64.6             | 60.9             |
| adjusted ebitda               | 1390.4           | 1289.9           | 1237.9           |
| adjusted ebitda margin        | 41.6% ( 41.6 % ) | 34.9% ( 34.9 % ) | 30.4% ( 30.4 % ) |

Question:
what is the increase in the operating margin observed in 2015 and 2016?


pre_text: 2015 vs .
2014 on a gaap basis , the effective tax rate was 24.0% ( 24.0 % ) and 27.1% ( 27.1 % ) in 2015 and 2014 , respectively .
the effective tax rate was higher in fiscal year 2014 primarily due to the goodwill impairment charge of $ 305.2 , which was not deductible for tax purposes , and the chilean tax reform enacted in september 2014 which increased income tax expense by $ 20.6 .
these impacts were partially offset by an income tax benefit of $ 51.6 associated with losses from transactions and a tax election in a non-u.s .
subsidiary .
refer to note 10 , goodwill , and note 23 , income taxes , to the consolidated financial statements for additional information .
on a non-gaap basis , the effective tax rate was 24.2% ( 24.2 % ) and 24.1% ( 24.1 % ) in 2015 and 2014 , respectively .
discontinued operations on 29 march 2016 , the board of directors approved the company 2019s exit of its energy-from-waste ( efw ) business .
as a result , efforts to start up and operate its two efw projects located in tees valley , united kingdom , have been discontinued .
the decision to exit the business and stop development of the projects was based on continued difficulties encountered and the company 2019s conclusion , based on testing and analysis completed during the second quarter of fiscal year 2016 , that significant additional time and resources would be required to make the projects operational .
in addition , the decision allows the company to execute its strategy of focusing resources on its core industrial gases business .
the efw segment has been presented as a discontinued operation .
prior year efw business segment information has been reclassified to conform to current year presentation .
in fiscal 2016 , our loss from discontinued operations , net of tax , of $ 884.2 primarily resulted from the write down of assets to their estimated net realizable value and to record a liability for plant disposition and other costs .
income tax benefits related only to one of the projects , as the other did not qualify for a local tax deduction .
the loss from discontinued operations also includes land lease costs , commercial and administrative costs , and costs incurred for ongoing project exit activities .
we expect additional exit costs of $ 50 to $ 100 to be recorded in future periods .
in fiscal 2015 , our loss from discontinued operations , net of tax , related to efw was $ 6.8 .
this resulted from costs for land leases and commercial and administrative expenses .
in fiscal 2014 , our loss from discontinued operations , net of tax , was $ 2.9 .
this included a loss , net of tax , of $ 7.5 for the cost of efw land leases and commercial and administrative expenses .
this loss was partially offset by a gain of $ 3.9 for the sale of the remaining homecare business and settlement of contingencies related to a sale of a separate portion of the business to the linde group in 2012 .
refer to note 4 , discontinued operations , for additional details .
segment analysis industrial gases 2013 americas .
post_text: .
label: 0.049
qa: answer: 4.9%
explanation: it is the variation between these operating margins .
ann_table_rows: 3
steps: op: minus1-1
arg1: 26.8%
arg2: 21.9%
res: 4.9%
program: subtract(26.8%, 21.9%)
gold_inds: table_3: the operating margin of 2016 is 26.8% ( 26.8 % ) ; the operating margin of 2015 is 21.9% ( 21.9 % ) ; the operating margin of 2014 is 18.7% ( 18.7 % ) ;
exe_ans: 0.049
tfidftopn: table_2: The operating income of 2016 is 895.2 ; The operating income of 2015 is 808.4 ; The operating income of 2014 is 762.6 ;
table_6: The adjusted ebitda margin of 2016 is 41.6% ( 41.6 % ) ; The adjusted ebitda margin of 2015 is 34.9% ( 34.9 % ) ; The adjusted ebitda margin of 2014 is 30.4% ( 30.4 % ) ;
program_re: subtract(26.8%, 21.9%)
model_input: table_1
the sales of 2016 is $ 3343.6 ; the sales of 2015 is $ 3693.9 ; the sales of 2014 is $ 4078.5 ;
table_2
the operating income of 2016 is 895.2 ; the operating income of 2015 is 808.4 ; the operating income of 2014 is 762.6 ;
table_3
the operating margin of 2016 is 26.8% ( 26.8 % ) ; the operating margin of 2015 is 21.9% ( 21.9 % ) ; the operating margin of 2014 is 18.7% ( 18.7 % ) ;