Years

P1

P2

P3

P4

Total

Length of phases

Base years

1961-1990

14

38

31

44

124

periods

2000-2030

12

36

31

43

119

2030-2050

9

35

30

40

112

Changes in length of

2000-2030

−2

−2

0

−1

−5

phases

2030-2050

−5

−3

−1

−4

−13