Year Percent
1950 0.541
1951 0.464
1952 0.353
1953 0.319
1954 0.346
1955 0.416
1956 0.513
1957 0.624
1958 0.735
1959 0.84
1960 0.943
1961 1.053
1962 1.186
1963 1.353
1964 1.549
1965 1.76
1966 1.962
1967 2.104
1968 2.146
1969 2.098
1970 2.002
1971 1.912
1972 1.867
1973 1.886
1974 1.97
1975 2.082
1976 2.188
1977 2.28
1978 2.357
1979 2.418
1980 2.471
1981 2.52
1982 2.57
1983 2.618
1984 2.664
1985 2.706
1986 2.741
1987 2.761
1988 2.76
1989 2.739
1990 2.71
1991 2.682
1992 2.652
1993 2.617
1994 2.58
1995 2.547
1996 2.522
1997 2.505
1998 2.495
1999 2.494
2000 2.497
2001 2.506
2002 2.544
2003 2.626
2004 2.746
2005 2.871
2006 2.977
2007 3.072
2008 3.173
2009 3.269
2010 3.362
2011 3.434
2012 3.421
2013 3.274
2014 3.014
2015 2.7
2016 2.401
2017 2.169
2018 2.031
2019 1.985
2020 1.984
2021 1.982
2022 1.967
2023 1.941
2024 1.904
2025 1.865
2026 1.832
2027 1.804
2028 1.779
2029 1.755
2030 1.732
2031 1.71
2032 1.689
2033 1.67
2034 1.65
2035 1.632
2036 1.613
2037 1.594
2038 1.574
2039 1.554
2040 1.533
2041 1.511
2042 1.489
2043 1.465
2044 1.44
2045 1.415
2046 1.388
2047 1.361
2048 1.334
2049 1.305
2050 1.276
2051 1.246
2052 1.217
2053 1.187
2054 1.158
2055 1.128
2056 1.099
2057 1.071
2058 1.043
2059 1.017
2060 0.991
2061 0.966
2062 0.942
2063 0.918
2064 0.896
2065 0.875
2066 0.854
2067 0.833
2068 0.814
2069 0.795
2070 0.776
2071 0.758
2072 0.74
2073 0.721
2074 0.703
2075 0.685
2076 0.667
2077 0.648
2078 0.63
2079 0.613
2080 0.595
2081 0.577
2082 0.559
2083 0.54
2084 0.522
2085 0.503
2086 0.485
2087 0.466
2088 0.447
2089 0.428
2090 0.409
2091 0.39
2092 0.371
2093 0.353
2094 0.335
2095 0.317
2096 0.3
2097 0.282
2098 0.265
2099 0.249