Percentage Component Bar Chart
A subdivided bar chart may be drawn on a percentage basis. To draw a subdivided bar chart on a percentage basis, we express each component as the percentage of its respective total. In drawing a percentage bar chart, bars of length equal to 100 for each class are drawn in the first step and subdivided into the proportion of the percentage of their component in the second step. The diagram so obtained is called a percentage component bar chart or percentage stacked bar chart. This type of chart is useful to make comparisons in components holding the difference of total constants.
Example:
The table below shows the quantity in hundred kgs of wheat, barley and oats produced in a certain form during the years 1991 to 1994.
Years

Wheat

Barley

Oats

1991

34

18

27

1992

43

14

24

1993

43

16

27

1994

45

13

34

Construct a percentage component bar chart to illustrate this data.
Solution:
The necessary computations for the construction of a percentage bar chart given below:
Item

1991

1992

1993

1994



%

Cum%

%

Cum%

%

Cum%

%

Cum%

Wheat

43.0

43.0

53.1

53.1

50.0

50.0

48.9

48.9

Barley

22.8

65.8

17.3

70.4

18.6

68.6

14.1

63.0

Oats

34.2

100

29.6

100

31.4

100

37.0

100

Total

100


100


100


100


 % indicates the percentage of each item
 Cum% indicates the cumulative percentage