1955  -9.0977  2.68021
1956  -7.57581  2.66767
1957  -7.76315  2.64586
1958  -3.31146  2.63143
1959  -5.51033  2.65378
1960  -3.86924  2.62898
1961  -2.15501  2.62517
1962  -0.973403  2.61198
1963  -2.56878  2.59951
1964  -3.81929  2.5874
1965  -3.69072  2.55925
1966  -3.16453  2.54322
1967  -4.39858  2.52006
1968  -6.47485  2.48065
1969  -5.91505  2.48138
1970  -4.25822  2.46616
1971  -2.57927  2.41873
1972  -1.5865  2.42438
1973  -1.01775  2.42885
1974  -1.37812  2.4617
1975  0.787616  2.47898
1976  -0.487566  2.44741
1977  0.0655651  2.44498
1978  -0.971079  2.43751
1979  -1.00344  2.41069
1980  3.88926  2.39652
1981  4.90713  2.40431
1982  3.82149  2.38904
1983  1.15168  2.38601
1984  3.15058  2.3961
1985  3.85427  2.36889
1986  3.80069  2.36928
1987  3.71623  2.34237
1988  6.13016  2.35179
1989  5.14954  2.36184
1990  6.02257  2.29457
1991  7.84665  2.30224
1992  6.34187  2.29442
1993  4.58413  2.28302
1994  5.95826  2.31548
1995  5.22858  2.29405
1996  8.34268  2.29853
1997  8.89367  2.29794
1998  8.05229  2.28885
1999  10.2508  2.29861
2000  9.6277  2.31454
2001  12.8279  2.32865
2002  15.8686  2.33077
2003  18.2838  2.27818
2004  17.0596  2.20475
2005  16.6133  2.1609
2006  16.8454  2.15612
2007  15.502  2.14505
2008  17.6176  2.15093
2009  19.0564  2.14621
2010  18.6179  2.14577
2011  19.0558  2.14781
2012  19.6988  2.14906
2013  21.4539  2.19506
2014  22.357  2.2002
2015  23.9835  2.18695
2016  22.821  2.18169
2017  25.3912  2.19188