Year Percent
1950 1.547
1951 1.469
1952 1.358
1953 1.323
1954 1.341
1955 1.392
1956 1.455
1957 1.513
1958 1.552
1959 1.568
1960 1.565
1961 1.558
1962 1.569
1963 1.613
1964 1.682
1965 1.768
1966 1.844
1967 1.844
1968 1.716
1969 1.474
1970 1.185
1971 0.92
1972 0.705
1973 0.549
1974 0.462
1975 0.413
1976 0.388
1977 0.449
1978 0.662
1979 1.016
1980 1.467
1981 1.942
1982 2.348
1983 2.622
1984 2.772
1985 2.819
1986 2.836
1987 3.015
1988 3.491
1989 4.195
1990 4.975
1991 5.613
1992 5.834
1993 5.497
1994 4.712
1995 3.754
1996 2.881
1997 2.229
1998 1.859
1999 1.763
2000 1.801
2001 1.832
2002 1.853
2003 1.895
2004 1.948
2005 2.02
2006 2.109
2007 2.187
2008 2.227
2009 2.231
2010 2.217
2011 2.208
2012 2.222
2013 2.27
2014 2.349
2015 2.44
2016 2.522
2017 2.581
2018 2.608
2019 2.606
2020 2.587
2021 2.567
2022 2.547
2023 2.528
2024 2.51
2025 2.491
2026 2.469
2027 2.445
2028 2.421
2029 2.397
2030 2.373
2031 2.348
2032 2.322
2033 2.296
2034 2.269
2035 2.242
2036 2.214
2037 2.187
2038 2.159
2039 2.132
2040 2.105
2041 2.077
2042 2.05
2043 2.022
2044 1.994
2045 1.966
2046 1.939
2047 1.911
2048 1.882
2049 1.853
2050 1.825
2051 1.796
2052 1.767
2053 1.739
2054 1.711
2055 1.684
2056 1.657
2057 1.629
2058 1.601
2059 1.573
2060 1.546
2061 1.518
2062 1.49
2063 1.463
2064 1.436
2065 1.409
2066 1.383
2067 1.356
2068 1.33
2069 1.304
2070 1.278
2071 1.253
2072 1.227
2073 1.202
2074 1.178
2075 1.154
2076 1.13
2077 1.106
2078 1.082
2079 1.058
2080 1.034
2081 1.01
2082 0.987
2083 0.964
2084 0.942
2085 0.919
2086 0.897
2087 0.875
2088 0.853
2089 0.831
2090 0.809
2091 0.788
2092 0.767
2093 0.746
2094 0.726
2095 0.706
2096 0.687
2097 0.668
2098 0.649
2099 0.63