Year Percent
1950 3.33
1951 3.207
1952 3.023
1953 2.946
1954 2.946
1955 2.994
1956 3.067
1957 3.144
1958 3.211
1959 3.26
1960 3.296
1961 3.329
1962 3.374
1963 3.44
1964 3.52
1965 3.605
1966 3.675
1967 3.674
1968 3.563
1969 3.359
1970 3.113
1971 2.882
1972 2.716
1973 2.643
1974 2.657
1975 2.713
1976 2.761
1977 2.782
1978 2.767
1979 2.719
1980 2.656
1981 2.599
1982 2.554
1983 2.526
1984 2.511
1985 2.5
1986 2.482
1987 2.459
1988 2.434
1989 2.406
1990 2.376
1991 2.341
1992 2.286
1993 2.198
1994 2.08
1995 1.951
1996 1.83
1997 1.716
1998 1.606
1999 1.504
2000 1.407
2001 1.316
2002 1.259
2003 1.255
2004 1.302
2005 1.376
2006 1.45
2007 1.512
2008 1.556
2009 1.581
2010 1.595
2011 1.607
2012 1.61
2013 1.597
2014 1.568
2015 1.529
2016 1.486
2017 1.439
2018 1.386
2019 1.328
2020 1.266
2021 1.205
2022 1.144
2023 1.087
2024 1.033
2025 0.982
2026 0.933
2027 0.887
2028 0.847
2029 0.814
2030 0.785
2031 0.757
2032 0.731
2033 0.707
2034 0.685
2035 0.665
2036 0.645
2037 0.625
2038 0.605
2039 0.583
2040 0.561
2041 0.538
2042 0.514
2043 0.488
2044 0.459
2045 0.428
2046 0.397
2047 0.367
2048 0.335
2049 0.304
2050 0.273
2051 0.242
2052 0.212
2053 0.183
2054 0.155
2055 0.128
2056 0.102
2057 0.078
2058 0.055
2059 0.034
2060 0.014
2061 -0.005
2062 -0.023
2063 -0.04
2064 -0.055
2065 -0.07
2066 -0.084
2067 -0.097
2068 -0.11
2069 -0.123
2070 -0.136
2071 -0.148
2072 -0.16
2073 -0.171
2074 -0.182
2075 -0.192
2076 -0.202
2077 -0.212
2078 -0.221
2079 -0.229
2080 -0.237
2081 -0.245
2082 -0.252
2083 -0.259
2084 -0.265
2085 -0.271
2086 -0.277
2087 -0.282
2088 -0.287
2089 -0.291
2090 -0.295
2091 -0.299
2092 -0.303
2093 -0.307
2094 -0.311
2095 -0.316
2096 -0.32
2097 -0.324
2098 -0.329
2099 -0.334