Year Percent
1950 3.804
1951 4.125
1952 4.616
1953 4.784
1954 4.795
1955 4.759
1956 4.661
1957 4.63
1958 4.674
1959 4.765
1960 4.906
1961 4.989
1962 4.97
1963 4.818
1964 4.535
1965 4.206
1966 3.912
1967 3.739
1968 3.712
1969 3.818
1970 3.997
1971 4.184
1972 4.28
1973 4.218
1974 4.037
1975 3.799
1976 3.614
1977 3.589
1978 3.794
1979 4.197
1980 4.668
1981 5.085
1982 5.384
1983 5.547
1984 5.579
1985 5.535
1986 5.475
1987 5.443
1988 5.447
1989 5.479
1990 5.514
1991 5.51
1992 5.424
1993 5.215
1994 4.917
1995 4.591
1996 4.29
1997 4.035
1998 3.843
1999 3.71
2000 3.598
2001 3.492
2002 3.402
2003 3.339
2004 3.301
2005 3.282
2006 3.26
2007 3.222
2008 3.161
2009 3.072
2010 2.976
2011 2.887
2012 2.811
2013 2.753
2014 2.711
2015 2.677
2016 2.642
2017 2.607
2018 2.568
2019 2.521
2020 2.471
2021 2.426
2022 2.386
2023 2.351
2024 2.324
2025 2.298
2026 2.27
2027 2.244
2028 2.218
2029 2.191
2030 2.164
2031 2.137
2032 2.11
2033 2.08
2034 2.048
2035 2.013
2036 1.979
2037 1.945
2038 1.909
2039 1.873
2040 1.835
2041 1.797
2042 1.76
2043 1.723
2044 1.683
2045 1.644
2046 1.606
2047 1.567
2048 1.531
2049 1.496
2050 1.46
2051 1.426
2052 1.393
2053 1.362
2054 1.331
2055 1.302
2056 1.272
2057 1.244
2058 1.215
2059 1.188
2060 1.161
2061 1.134
2062 1.108
2063 1.081
2064 1.057
2065 1.032
2066 1.007
2067 0.983
2068 0.958
2069 0.935
2070 0.91
2071 0.886
2072 0.863
2073 0.84
2074 0.816
2075 0.794
2076 0.771
2077 0.748
2078 0.726
2079 0.703
2080 0.681
2081 0.66
2082 0.638
2083 0.615
2084 0.593
2085 0.571
2086 0.548
2087 0.526
2088 0.506
2089 0.484
2090 0.463
2091 0.442
2092 0.421
2093 0.401
2094 0.381
2095 0.36
2096 0.338
2097 0.318
2098 0.299
2099 0.279