the free pie charts below show the changes in annual spending by a particular UK school in 1981 1991 and 2001

The three pie chart show the change total school spending by a particular UK school in 1981, 1991 and 2001.
There was a dramatical development in percentage of teacher’s salaries from 40% in 1981 to 50% in 1991. While other workers’ salaries virtually decreased from 28% in 1981 to only 15% in 2001. Moreover, teachers’salaries of total school spending in 1991 hold 50% and ending at 42% in 2001
Move on to others, resources books significantly fall from 20% in 1991 to 9% in 2001. By constract, furniture and equipment and insurance remarkably raised with 15%, 2% in 1981 and 23%, 8% in 2001 respectively.
Overall, staffs' salaries hold the highest percentage of total school spending when equipment and insurance were also considerably rised in each years. Beside that, books and other workers’ salaries were also decreased in expenditure.