As is show in these three pie charts, the annual expenses of a specific British school had changed in 1981, 1991, and 2001.

According to the pie chart, other workers’ wages kept falling during the three decades. In 1981, one-third of the expense on other workers’ wages shared by school, 22% in 1991, 15% in 2001. In contrast, expenditure on insurance increased from 2% to 8%.

Comparatively, other expenses had a noncontinuous change in total. Teachers’ salaries covered 40% in 1981, increased to a half in 1991 but in 2001 the percentage decrease to 45%. There was a significant decrease in furniture and equipment from 15% to 5%, but it ascended by 18% in 2001. In the period of three decades, the resource in school grew 5% from 1981 to 1991, and then slid to 9%.

Overall, teachers’ salaries took up the largest proportion meanwhile the insurance covered the smallest percentage no matter how it changed during three decades.