Year Percent
1950 2.974
1951 2.904
1952 2.748
1953 2.58
1954 2.426
1955 2.308
1956 2.276
1957 2.356
1958 2.534
1959 2.798
1960 3.13
1961 3.449
1962 3.663
1963 3.731
1964 3.663
1965 3.533
1966 3.408
1967 3.326
1968 3.302
1969 3.325
1970 3.372
1971 3.404
1972 3.4
1973 3.354
1974 3.267
1975 3.164
1976 3.061
1977 2.983
1978 2.947
1979 2.944
1980 2.948
1981 2.938
1982 2.912
1983 2.871
1984 2.815
1985 2.762
1986 2.707
1987 2.614
1988 2.454
1989 2.226
1990 1.96
1991 1.707
1992 1.542
1993 1.515
1994 1.618
1995 1.788
1996 1.945
1997 2.032
1998 2.019
1999 1.908
2000 1.755
2001 1.607
2002 1.475
2003 1.363
2004 1.269
2005 1.189
2006 1.107
2007 1.026
2008 0.948
2009 0.874
2010 0.796
2011 0.72
2012 0.678
2013 0.691
2014 0.755
2015 0.85
2016 0.948
2017 0.998
2018 0.962
2019 0.847
2020 0.685
2021 0.529
2022 0.419
2023 0.384
2024 0.426
2025 0.508
2026 0.586
2027 0.636
2028 0.651
2029 0.623
2030 0.574
2031 0.529
2032 0.493
2033 0.461
2034 0.436
2035 0.414
2036 0.391
2037 0.366
2038 0.34
2039 0.317
2040 0.294
2041 0.27
2042 0.246
2043 0.223
2044 0.203
2045 0.182
2046 0.158
2047 0.137
2048 0.119
2049 0.098
2050 0.077
2051 0.059
2052 0.04
2053 0.022
2054 0.005
2055 -0.011
2056 -0.026
2057 -0.042
2058 -0.056
2059 -0.07
2060 -0.083
2061 -0.094
2062 -0.106
2063 -0.12
2064 -0.13
2065 -0.14
2066 -0.151
2067 -0.162
2068 -0.173
2069 -0.182
2070 -0.192
2071 -0.202
2072 -0.211
2073 -0.219
2074 -0.231
2075 -0.241
2076 -0.251
2077 -0.26
2078 -0.27
2079 -0.278
2080 -0.287
2081 -0.299
2082 -0.306
2083 -0.315
2084 -0.323
2085 -0.332
2086 -0.337
2087 -0.344
2088 -0.351
2089 -0.355
2090 -0.36
2091 -0.364
2092 -0.368
2093 -0.372
2094 -0.375
2095 -0.377
2096 -0.381
2097 -0.383
2098 -0.384
2099 -0.385