Year Percent
1950 2.581
1951 2.564
1952 2.538
1953 2.528
1954 2.529
1955 2.538
1956 2.551
1957 2.567
1958 2.584
1959 2.598
1960 2.611
1961 2.622
1962 2.632
1963 2.641
1964 2.647
1965 2.655
1966 2.662
1967 2.654
1968 2.616
1969 2.554
1970 2.482
1971 2.419
1972 2.382
1973 2.383
1974 2.42
1975 2.472
1976 2.522
1977 2.575
1978 2.639
1979 2.71
1980 2.781
1981 2.843
1982 2.885
1983 2.9
1984 2.887
1985 2.86
1986 2.827
1987 2.787
1988 2.735
1989 2.674
1990 2.605
1991 2.533
1992 2.465
1993 2.406
1994 2.354
1995 2.305
1996 2.254
1997 2.195
1998 2.129
1999 2.054
2000 1.978
2001 1.905
2002 1.828
2003 1.74
2004 1.645
2005 1.546
2006 1.451
2007 1.377
2008 1.337
2009 1.328
2010 1.336
2011 1.345
2012 1.348
2013 1.341
2014 1.323
2015 1.301
2016 1.28
2017 1.26
2018 1.238
2019 1.213
2020 1.188
2021 1.162
2022 1.134
2023 1.106
2024 1.076
2025 1.046
2026 1.016
2027 0.986
2028 0.956
2029 0.927
2030 0.898
2031 0.869
2032 0.841
2033 0.812
2034 0.783
2035 0.754
2036 0.725
2037 0.697
2038 0.67
2039 0.644
2040 0.619
2041 0.594
2042 0.57
2043 0.547
2044 0.524
2045 0.502
2046 0.48
2047 0.458
2048 0.437
2049 0.416
2050 0.396
2051 0.376
2052 0.356
2053 0.335
2054 0.314
2055 0.293
2056 0.272
2057 0.25
2058 0.228
2059 0.206
2060 0.183
2061 0.16
2062 0.138
2063 0.115
2064 0.092
2065 0.069
2066 0.047
2067 0.025
2068 0.003
2069 -0.018
2070 -0.038
2071 -0.058
2072 -0.078
2073 -0.096
2074 -0.115
2075 -0.132
2076 -0.149
2077 -0.165
2078 -0.179
2079 -0.192
2080 -0.205
2081 -0.216
2082 -0.226
2083 -0.236
2084 -0.244
2085 -0.251
2086 -0.257
2087 -0.264
2088 -0.269
2089 -0.275
2090 -0.28
2091 -0.286
2092 -0.291
2093 -0.295
2094 -0.3
2095 -0.304
2096 -0.309
2097 -0.314
2098 -0.319
2099 -0.325