Year Percent
1950 3.04
1951 2.9
1952 2.653
1953 2.462
1954 2.32
1955 2.226
1956 2.175
1957 2.165
1958 2.195
1959 2.257
1960 2.344
1961 2.445
1962 2.549
1963 2.648
1964 2.739
1965 2.829
1966 2.924
1967 3.017
1968 3.099
1969 3.172
1970 3.233
1971 3.285
1972 3.355
1973 3.462
1974 3.597
1975 3.736
1976 3.849
1977 3.907
1978 3.894
1979 3.816
1980 3.708
1981 3.599
1982 3.493
1983 3.387
1984 3.283
1985 3.177
1986 3.066
1987 2.967
1988 2.893
1989 2.84
1990 2.798
1991 2.75
1992 2.678
1993 2.57
1994 2.429
1995 2.278
1996 2.138
1997 2.003
1998 1.865
1999 1.728
2000 1.594
2001 1.471
2002 1.388
2003 1.368
2004 1.407
2005 1.479
2006 1.553
2007 1.622
2008 1.681
2009 1.73
2010 1.773
2011 1.814
2012 1.846
2013 1.862
2014 1.86
2015 1.849
2016 1.832
2017 1.81
2018 1.778
2019 1.739
2020 1.694
2021 1.647
2022 1.6
2023 1.556
2024 1.514
2025 1.473
2026 1.432
2027 1.392
2028 1.355
2029 1.32
2030 1.286
2031 1.253
2032 1.221
2033 1.191
2034 1.162
2035 1.134
2036 1.107
2037 1.08
2038 1.053
2039 1.027
2040 1.001
2041 0.976
2042 0.949
2043 0.923
2044 0.895
2045 0.868
2046 0.84
2047 0.811
2048 0.782
2049 0.753
2050 0.722
2051 0.692
2052 0.662
2053 0.632
2054 0.603
2055 0.573
2056 0.544
2057 0.515
2058 0.487
2059 0.459
2060 0.432
2061 0.406
2062 0.38
2063 0.356
2064 0.332
2065 0.31
2066 0.289
2067 0.269
2068 0.25
2069 0.232
2070 0.215
2071 0.199
2072 0.184
2073 0.17
2074 0.157
2075 0.145
2076 0.133
2077 0.121
2078 0.109
2079 0.098
2080 0.087
2081 0.076
2082 0.064
2083 0.053
2084 0.042
2085 0.03
2086 0.018
2087 0.007
2088 -0.005
2089 -0.017
2090 -0.029
2091 -0.041
2092 -0.053
2093 -0.064
2094 -0.075
2095 -0.086
2096 -0.097
2097 -0.107
2098 -0.117
2099 -0.127