Year Percent
1950 2.219
1951 2.33
1952 2.523
1953 2.659
1954 2.752
1955 2.817
1956 2.854
1957 2.877
1958 2.899
1959 2.919
1960 2.939
1961 2.964
1962 2.986
1963 2.994
1964 3.005
1965 3.012
1966 3.014
1967 3.058
1968 3.173
1969 3.344
1970 3.532
1971 3.699
1972 3.803
1973 3.828
1974 3.783
1975 3.699
1976 3.612
1977 3.537
1978 3.474
1979 3.423
1980 3.379
1981 3.331
1982 3.27
1983 3.186
1984 3.085
1985 2.979
1986 2.881
1987 2.811
1988 2.778
1989 2.782
1990 2.805
1991 2.823
1992 2.834
1993 2.838
1994 2.83
1995 2.818
1996 2.804
1997 2.786
1998 2.764
1999 2.735
2000 2.704
2001 2.672
2002 2.633
2003 2.581
2004 2.522
2005 2.458
2006 2.395
2007 2.339
2008 2.294
2009 2.259
2010 2.23
2011 2.2
2012 2.167
2013 2.127
2014 2.083
2015 2.036
2016 1.991
2017 1.952
2018 1.918
2019 1.89
2020 1.866
2021 1.842
2022 1.82
2023 1.801
2024 1.782
2025 1.766
2026 1.75
2027 1.734
2028 1.718
2029 1.701
2030 1.685
2031 1.669
2032 1.65
2033 1.631
2034 1.61
2035 1.587
2036 1.564
2037 1.54
2038 1.515
2039 1.49
2040 1.463
2041 1.435
2042 1.408
2043 1.379
2044 1.349
2045 1.318
2046 1.288
2047 1.259
2048 1.232
2049 1.208
2050 1.184
2051 1.162
2052 1.139
2053 1.117
2054 1.093
2055 1.071
2056 1.05
2057 1.029
2058 1.009
2059 0.99
2060 0.972
2061 0.955
2062 0.937
2063 0.919
2064 0.901
2065 0.883
2066 0.864
2067 0.846
2068 0.827
2069 0.809
2070 0.79
2071 0.771
2072 0.752
2073 0.733
2074 0.712
2075 0.692
2076 0.672
2077 0.651
2078 0.631
2079 0.609
2080 0.588
2081 0.567
2082 0.547
2083 0.526
2084 0.505
2085 0.485
2086 0.466
2087 0.446
2088 0.428
2089 0.41
2090 0.393
2091 0.376
2092 0.36
2093 0.343
2094 0.327
2095 0.311
2096 0.296
2097 0.282
2098 0.267
2099 0.254