Year Percent
1950 1.91
1951 1.95
1952 2.023
1953 2.083
1954 2.134
1955 2.179
1956 2.221
1957 2.262
1958 2.304
1959 2.348
1960 2.393
1961 2.438
1962 2.48
1963 2.514
1964 2.546
1965 2.568
1966 2.579
1967 2.611
1968 2.688
1969 2.8
1970 2.931
1971 3.048
1972 3.088
1973 3.003
1974 2.811
1975 2.584
1976 2.393
1977 2.253
1978 2.167
1979 2.139
1980 2.125
1981 2.112
1982 2.214
1983 2.527
1984 3.016
1985 3.579
1986 4.082
1987 4.375
1988 4.375
1989 4.122
1990 3.746
1991 3.383
1992 3.116
1993 2.981
1994 2.967
1995 3.012
1996 3.036
1997 2.96
1998 2.739
1999 2.391
2000 1.993
2001 1.629
2002 1.351
2003 1.186
2004 1.136
2005 1.144
2006 1.161
2007 1.217
2008 1.355
2009 1.561
2010 1.806
2011 2.046
2012 2.227
2013 2.31
2014 2.3
2015 2.242
2016 2.183
2017 2.133
2018 2.091
2019 2.058
2020 2.026
2021 1.988
2022 1.949
2023 1.912
2024 1.88
2025 1.85
2026 1.82
2027 1.789
2028 1.758
2029 1.728
2030 1.697
2031 1.667
2032 1.639
2033 1.612
2034 1.588
2035 1.564
2036 1.541
2037 1.518
2038 1.496
2039 1.474
2040 1.453
2041 1.431
2042 1.41
2043 1.387
2044 1.364
2045 1.34
2046 1.316
2047 1.291
2048 1.265
2049 1.237
2050 1.209
2051 1.181
2052 1.153
2053 1.124
2054 1.095
2055 1.066
2056 1.036
2057 1.007
2058 0.979
2059 0.951
2060 0.924
2061 0.896
2062 0.87
2063 0.843
2064 0.816
2065 0.79
2066 0.764
2067 0.739
2068 0.714
2069 0.69
2070 0.666
2071 0.642
2072 0.619
2073 0.597
2074 0.575
2075 0.554
2076 0.533
2077 0.512
2078 0.491
2079 0.471
2080 0.45
2081 0.43
2082 0.411
2083 0.392
2084 0.373
2085 0.356
2086 0.338
2087 0.32
2088 0.303
2089 0.286
2090 0.27
2091 0.253
2092 0.237
2093 0.221
2094 0.205
2095 0.19
2096 0.175
2097 0.159
2098 0.144
2099 0.129