Year Percent
1950 0.494
1951 0.984
1952 1.939
1953 2.8
1954 3.495
1955 3.971
1956 4.189
1957 4.14
1958 3.837
1959 3.324
1960 2.695
1961 2.076
1962 1.611
1963 1.418
1964 1.493
1965 1.698
1966 1.894
1967 2.079
1968 2.284
1969 2.495
1970 2.723
1971 2.957
1972 3.124
1973 3.161
1974 3.088
1975 2.966
1976 2.867
1977 2.846
1978 2.933
1979 3.118
1980 3.326
1981 3.501
1982 3.684
1983 3.922
1984 4.191
1985 4.465
1986 4.692
1987 4.754
1988 4.573
1989 4.194
1990 3.736
1991 3.318
1992 3.008
1993 2.833
1994 2.79
1995 2.807
1996 2.824
1997 2.846
1998 2.895
1999 2.964
2000 3.045
2001 3.127
2002 3.19
2003 3.22
2004 3.218
2005 3.2
2006 3.182
2007 3.169
2008 3.161
2009 3.158
2010 3.155
2011 3.148
2012 3.134
2013 3.112
2014 3.083
2015 3.05
2016 3.016
2017 2.982
2018 2.947
2019 2.911
2020 2.875
2021 2.838
2022 2.8
2023 2.763
2024 2.726
2025 2.688
2026 2.65
2027 2.613
2028 2.574
2029 2.536
2030 2.498
2031 2.46
2032 2.421
2033 2.382
2034 2.342
2035 2.303
2036 2.263
2037 2.222
2038 2.181
2039 2.139
2040 2.097
2041 2.055
2042 2.013
2043 1.971
2044 1.928
2045 1.887
2046 1.845
2047 1.804
2048 1.764
2049 1.725
2050 1.687
2051 1.649
2052 1.612
2053 1.576
2054 1.54
2055 1.505
2056 1.47
2057 1.436
2058 1.403
2059 1.37
2060 1.337
2061 1.305
2062 1.273
2063 1.242
2064 1.211
2065 1.181
2066 1.151
2067 1.12
2068 1.09
2069 1.06
2070 1.03
2071 1
2072 0.97
2073 0.94
2074 0.91
2075 0.88
2076 0.85
2077 0.821
2078 0.792
2079 0.763
2080 0.734
2081 0.706
2082 0.678
2083 0.651
2084 0.625
2085 0.599
2086 0.574
2087 0.549
2088 0.524
2089 0.499
2090 0.475
2091 0.451
2092 0.427
2093 0.405
2094 0.383
2095 0.362
2096 0.341
2097 0.321
2098 0.302
2099 0.283