Year Percent
1950 1.782
1951 1.688
1952 1.508
1953 1.346
1954 1.201
1955 1.076
1956 0.97
1957 0.886
1958 0.823
1959 0.781
1960 0.756
1961 0.741
1962 0.731
1963 0.719
1964 0.704
1965 0.69
1966 0.682
1967 0.687
1968 0.713
1969 0.756
1970 0.808
1971 0.859
1972 0.902
1973 0.933
1974 0.951
1975 0.961
1976 0.968
1977 0.966
1978 0.947
1979 0.914
1980 0.873
1981 0.833
1982 0.79
1983 0.739
1984 0.684
1985 0.613
1986 0.531
1987 0.486
1988 0.524
1989 0.636
1990 0.799
1991 0.956
1992 0.993
1993 0.821
1994 0.45
1995 -0.032
1996 -0.512
1997 -0.88
1998 -1.054
1999 -1.022
2000 -0.873
2001 -0.716
2002 -0.591
2003 -0.507
2004 -0.475
2005 -0.461
2006 -0.435
2007 -0.404
2008 -0.387
2009 -0.385
2010 -0.393
2011 -0.404
2012 -0.41
2013 -0.405
2014 -0.388
2015 -0.365
2016 -0.344
2017 -0.33
2018 -0.326
2019 -0.333
2020 -0.345
2021 -0.359
2022 -0.372
2023 -0.384
2024 -0.395
2025 -0.407
2026 -0.419
2027 -0.433
2028 -0.447
2029 -0.461
2030 -0.476
2031 -0.491
2032 -0.506
2033 -0.52
2034 -0.534
2035 -0.548
2036 -0.561
2037 -0.572
2038 -0.582
2039 -0.59
2040 -0.596
2041 -0.602
2042 -0.606
2043 -0.609
2044 -0.61
2045 -0.61
2046 -0.609
2047 -0.608
2048 -0.606
2049 -0.605
2050 -0.603
2051 -0.601
2052 -0.6
2053 -0.601
2054 -0.603
2055 -0.606
2056 -0.61
2057 -0.614
2058 -0.618
2059 -0.624
2060 -0.629
2061 -0.635
2062 -0.641
2063 -0.646
2064 -0.651
2065 -0.655
2066 -0.659
2067 -0.663
2068 -0.665
2069 -0.667
2070 -0.668
2071 -0.668
2072 -0.667
2073 -0.667
2074 -0.665
2075 -0.663
2076 -0.66
2077 -0.657
2078 -0.652
2079 -0.648
2080 -0.642
2081 -0.637
2082 -0.631
2083 -0.625
2084 -0.619
2085 -0.614
2086 -0.608
2087 -0.602
2088 -0.596
2089 -0.591
2090 -0.586
2091 -0.581
2092 -0.575
2093 -0.57
2094 -0.565
2095 -0.559
2096 -0.554
2097 -0.548
2098 -0.543
2099 -0.538