The chart s how the percentage of people in different sectors in Town A and B in two years 1960 and 2010

The pie chart compares the percentage of worker in three different categories manufacturing, sales and services from two towns in 1960 and 2010.
Overall, the amount of people working in manufacturing increase 2010 compare to its figure in 1960. In contrast, there is a decrease in the sales workforce by 2010.
In town A, the proportion of manufacturing worker was 29%, almost three time higher than town B and keep it rising in both town and finally reach 64% in town A and 25% in town B by 2010. In contrast, the figures for the sales sector experienced a declined from 41% in 1960 to 20% in 2010 in town A. The same happened to town B which it decrease from 70% to 53% over the 50 years period.
As for the services sector, the percentage of worker almost halved in town A to 16% in 2010. While in town B it increase from 20% in 1960 to 22% in 2010.