Year Percent
1950 0.578
1951 0.627
1952 0.711
1953 0.769
1954 0.804
1955 0.818
1956 0.813
1957 0.792
1958 0.755
1959 0.707
1960 0.652
1961 0.595
1962 0.544
1963 0.503
1964 0.475
1965 0.454
1966 0.436
1967 0.439
1968 0.48
1969 0.557
1970 0.655
1971 0.755
1972 0.842
1973 0.906
1974 0.946
1975 0.969
1976 0.986
1977 1.01
1978 1.052
1979 1.107
1980 1.164
1981 1.207
1982 1.215
1983 1.172
1984 1.081
1985 0.966
1986 0.851
1987 0.722
1988 0.562
1989 0.376
1990 0.175
1991 -0.024
1992 -0.178
1993 -0.248
1994 -0.233
1995 -0.166
1996 -0.088
1997 -0.025
1998 0.009
1999 0.013
2000 0.001
2001 -0.006
2002 0.015
2003 0.08
2004 0.184
2005 0.309
2006 0.43
2007 0.515
2008 0.541
2009 0.507
2010 0.441
2011 0.371
2012 0.308
2013 0.253
2014 0.209
2015 0.169
2016 0.125
2017 0.082
2018 0.046
2019 0.019
2020 -0.003
2021 -0.024
2022 -0.046
2023 -0.068
2024 -0.091
2025 -0.114
2026 -0.136
2027 -0.156
2028 -0.174
2029 -0.19
2030 -0.204
2031 -0.218
2032 -0.231
2033 -0.242
2034 -0.251
2035 -0.258
2036 -0.265
2037 -0.272
2038 -0.279
2039 -0.285
2040 -0.292
2041 -0.298
2042 -0.305
2043 -0.313
2044 -0.321
2045 -0.33
2046 -0.339
2047 -0.348
2048 -0.359
2049 -0.37
2050 -0.381
2051 -0.393
2052 -0.404
2053 -0.414
2054 -0.424
2055 -0.433
2056 -0.441
2057 -0.448
2058 -0.455
2059 -0.46
2060 -0.464
2061 -0.467
2062 -0.469
2063 -0.469
2064 -0.468
2065 -0.464
2066 -0.46
2067 -0.454
2068 -0.447
2069 -0.438
2070 -0.428
2071 -0.416
2072 -0.403
2073 -0.389
2074 -0.374
2075 -0.358
2076 -0.341
2077 -0.323
2078 -0.305
2079 -0.286
2080 -0.268
2081 -0.249
2082 -0.231
2083 -0.214
2084 -0.198
2085 -0.184
2086 -0.17
2087 -0.157
2088 -0.147
2089 -0.138
2090 -0.132
2091 -0.126
2092 -0.122
2093 -0.12
2094 -0.119
2095 -0.119
2096 -0.121
2097 -0.125
2098 -0.131
2099 -0.14