IELTS: Graph of the winter heating costs from 2003 to 2011

The graph shows the winter heating costs because of heating fuel type from 2003 to 2011.

In general, fuel oil has highest costs for consumers than electricity and natural gas. Although, electricity has lowest costs than others.

Electricity has small costs in winter seasons that started from $343 to $460 in the final. The costs increase step by step in every year. For natural gas, the costs increase slightly from April 2003 to June 2005 then decline twice until November 2010, from $627 to $547. However, fuel oil has biggest costs for consumers then increased sharply every year, started from $928 in April 2003 to $2425 in November 2010.

Interestingly, in October 2009 until November 2010, costs of electricity and natural gas have almost same value. It is very different than other years.

To summary, there are many costumers use winter heating in winter seasons, specially about fuel oil then followed by natural gas and electricity.

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  Winter_heating.JPG
  

- it is not given! You just have to report what you see.

Plus, you don't have to have conclusion in the first task of IELTS.
Have these three parts:
1.Introduction
2.Overall view
3.Detailed information

I am also studying, let me share some alteration about your introduction


Here my try
The line graph shows the winter heating cost in the field of natural gas, fuel oil and electricity consuming by elderly during a-particular period from 2003 to 2011.

or
The line graph illustrates the number of winter heating expenditure which is consumed by elderly during a-particular period from 2003 to 2011
hopefully it helps you :D

Listing paragraph. I suggest you to make this paragraph with comparation and contrast. The second suggestion is that you should divide the detail information into two body paragraphs with the same proportion of sentence.