Table 4 Proportion of differences in contribution within the eastern, central and western regions

2011

56.48

9.89

33.63

2.82

1.39

95.79

2012

51.55

11.13

37.32

2.47

1.52

96.02

2013

49.15

12.06

38.78

2.20

1.70

96.10

2014

45.18

16.53

38.29

1.96

1.85

96.19

2015

40.68

19.18

40.14

1.74

1.92

96.34

2016

38.36

20.42

41.22

1.68

2.10

96.22

2017

30.87

22.21

46.91

1.39

1.94

96.67

2018

28.29

23.67

48.04

1.16

2.17

96.67

2019

25.21

23.22

51.58

1.06

2.05

96.89

2020

22.02

25.67

52.31

0.92

2.36

96.72