Year

$S_1\left(t\right)$

$S_2\left(t\right)$

$b=\left(S_2\left(t\right)-S_1\right)$

a

1992

4.56

7.062

2.5

−8.44074

1993

4.17

7.75

3.58

−7.36074

1994

4.55

7.85

3.3

−7.64074

1995

4.62

6.94

2.32

−8.62074

1996

4.23

11.56

7.31

−3.63074

1997

4.17

10.95

6.78

−4.16074

1998

4.78

11.19

6.41

−4.53074

1999

4.65

12.31

7.66

−3.28074

2000

4.53

11.25

6.72

−4.22074

2001

4.45

2.45

8

−2.94074

2002

4.62

14.32

9.7

−1.24074

2003

4

15.45

11.45

0.50926

2004

4.52

16.2

11.68

0.73926

2005

6.71

17.19

10.48

−0.46074

2006

8.3

20.89

12.59

1.64926

2007

12.13

24.38

12.25

1.30926

2008

13.51

29.34

15.83

4.88926

2009

19.51

32.27

12.76

1.81926

2010

24.23

30.67

6.44

−4.50074

2011

23.64

31.31

7.67

−3.27074

2012

14.4

37.56

23.16

12.21926

2013

15.45

41.35

25.9

14.95926

2014

29

45.64

16.64

5.69926

2015

12.5

41.78

29.28

18.33926

2016

33

45.9

12.9

1.95926

2017

32.73

42.57

9.84

−1.10074

2018

32.2

44.45

12.25

1.30926

Mean ()

12.4

10.94074

23.35