Year Percent
1950 2.326
1951 2.352
1952 2.405
1953 2.46
1954 2.513
1955 2.563
1956 2.607
1957 2.645
1958 2.674
1959 2.697
1960 2.716
1961 2.732
1962 2.752
1963 2.777
1964 2.808
1965 2.835
1966 2.854
1967 2.876
1968 2.909
1969 2.95
1970 3.001
1971 3.048
1972 3.05
1973 2.973
1974 2.831
1975 2.659
1976 2.502
1977 2.415
1978 2.431
1979 2.543
1980 2.699
1981 2.845
1982 2.956
1983 3.025
1984 3.054
1985 3.059
1986 3.059
1987 3.059
1988 3.057
1989 3.054
1990 3.051
1991 3.043
1992 3.005
1993 2.917
1994 2.788
1995 2.642
1996 2.508
1997 2.416
1998 2.386
1999 2.413
2000 2.47
2001 2.529
2002 2.579
2003 2.619
2004 2.648
2005 2.669
2006 2.692
2007 2.724
2008 2.774
2009 2.836
2010 2.902
2011 2.958
2012 2.989
2013 2.984
2014 2.945
2015 2.89
2016 2.834
2017 2.785
2018 2.741
2019 2.705
2020 2.672
2021 2.638
2022 2.603
2023 2.571
2024 2.54
2025 2.511
2026 2.483
2027 2.457
2028 2.432
2029 2.409
2030 2.387
2031 2.366
2032 2.344
2033 2.323
2034 2.302
2035 2.28
2036 2.258
2037 2.236
2038 2.213
2039 2.189
2040 2.164
2041 2.139
2042 2.113
2043 2.086
2044 2.058
2045 2.029
2046 2
2047 1.971
2048 1.942
2049 1.913
2050 1.883
2051 1.854
2052 1.825
2053 1.796
2054 1.768
2055 1.74
2056 1.713
2057 1.686
2058 1.66
2059 1.635
2060 1.61
2061 1.586
2062 1.563
2063 1.54
2064 1.517
2065 1.495
2066 1.474
2067 1.452
2068 1.43
2069 1.409
2070 1.387
2071 1.366
2072 1.344
2073 1.323
2074 1.302
2075 1.28
2076 1.259
2077 1.238
2078 1.217
2079 1.195
2080 1.174
2081 1.153
2082 1.131
2083 1.11
2084 1.087
2085 1.065
2086 1.043
2087 1.021
2088 0.999
2089 0.978
2090 0.958
2091 0.937
2092 0.917
2093 0.896
2094 0.876
2095 0.856
2096 0.836
2097 0.817
2098 0.798
2099 0.78