Year Percent
1950 2.504
1951 2.506
1952 2.511
1953 2.512
1954 2.512
1955 2.507
1956 2.5
1957 2.488
1958 2.473
1959 2.455
1960 2.436
1961 2.417
1962 2.401
1963 2.39
1964 2.383
1965 2.378
1966 2.372
1967 2.369
1968 2.371
1969 2.378
1970 2.387
1971 2.395
1972 2.394
1973 2.379
1974 2.352
1975 2.316
1976 2.278
1977 2.251
1978 2.243
1979 2.251
1980 2.267
1981 2.278
1982 2.265
1983 2.219
1984 2.142
1985 2.051
1986 1.963
1987 1.884
1988 1.817
1989 1.763
1990 1.714
1991 1.666
1992 1.626
1993 1.602
1994 1.592
1995 1.589
1996 1.587
1997 1.579
1998 1.561
1999 1.534
2000 1.506
2001 1.482
2002 1.454
2003 1.411
2004 1.357
2005 1.293
2006 1.232
2007 1.205
2008 1.236
2009 1.322
2010 1.43
2011 1.527
2012 1.594
2013 1.623
2014 1.613
2015 1.586
2016 1.556
2017 1.49
2018 1.354
2019 1.158
2020 0.927
2021 0.701
2022 0.523
2023 0.43
2024 0.42
2025 0.456
2026 0.494
2027 0.523
2028 0.543
2029 0.551
2030 0.555
2031 0.565
2032 0.571
2033 0.564
2034 0.543
2035 0.516
2036 0.487
2037 0.46
2038 0.435
2039 0.413
2040 0.393
2041 0.371
2042 0.349
2043 0.326
2044 0.303
2045 0.28
2046 0.257
2047 0.235
2048 0.213
2049 0.191
2050 0.17
2051 0.148
2052 0.127
2053 0.105
2054 0.083
2055 0.061
2056 0.039
2057 0.018
2058 -0.003
2059 -0.023
2060 -0.043
2061 -0.062
2062 -0.08
2063 -0.099
2064 -0.116
2065 -0.133
2066 -0.15
2067 -0.166
2068 -0.181
2069 -0.195
2070 -0.208
2071 -0.22
2072 -0.232
2073 -0.244
2074 -0.255
2075 -0.265
2076 -0.276
2077 -0.285
2078 -0.294
2079 -0.303
2080 -0.311
2081 -0.318
2082 -0.326
2083 -0.333
2084 -0.342
2085 -0.35
2086 -0.357
2087 -0.365
2088 -0.372
2089 -0.378
2090 -0.384
2091 -0.389
2092 -0.394
2093 -0.399
2094 -0.404
2095 -0.408
2096 -0.412
2097 -0.415
2098 -0.417
2099 -0.418