Read the sample answer on the topic: The pie charts show the annual spending of a school in UK.
The three pie charts below show the changes in annual spending by a particular UK school in 1981, 1991 and 2001.
Summarise the information by selecting and reporting the main features, and make comparisons where relevant.

Introduction
The three pie charts illustrate how the annual expenditure of a specific UK school changed in the years 1981, 1991, and 2001.
Overview
Overall, teachers’ salaries remained the largest expense, while spending on other workers’ salaries declined. Meanwhile, furniture and equipment costs fluctuated, and insurance expenditure gradually increased.
Body Paragraph
In 1981, teachers’ salaries accounted for approximately 40% of total school expenses, rising to about 50% in 1991 before decreasing by 5% in 2001. Meanwhile, spending on furniture and equipment fluctuated, starting at 15% in 1981, dropping to 5% in 1991, and then rising significantly to nearly a quarter of total expenses in 2001.
Resources such as books also saw variations, with expenditure at 15% in 1981, increasing to 20% in 1991, but declining to just 9% in 2001. Lastly, salaries for other staff made up 28% of the total budget in 1981, decreasing to 22% in 1991 and further dropping to 15% in 2001.
Finally, insurance constituted the smallest portion of school spending in all three years. It accounts for only two percent in 1981, rose slightly to three percent in 1991, and then experienced a more notable increase to 8% in 2001.
Biggest Mistake in IELTS Writing Task 1 (Academic)
In this sample answer, the student has used the present simple tense, which is wrong.
In IELTS Writing task 1, we should use the verb tense according to the date of the data. If the data is of the past, we will use past tense and so on.
To learn more tips on IELTS Writing Task 1 visit this link. Read more sample answers on line graphs from here.