Year Percent
1950 2.55
1951 2.587
1952 2.652
1953 2.702
1954 2.741
1955 2.772
1956 2.799
1957 2.826
1958 2.852
1959 2.881
1960 2.909
1961 2.937
1962 2.959
1963 2.976
1964 2.987
1965 2.994
1966 3
1967 3.016
1968 3.051
1969 3.1
1970 3.156
1971 3.206
1972 3.237
1973 3.238
1974 3.215
1975 3.179
1976 3.145
1977 3.121
1978 3.11
1979 3.113
1980 3.123
1981 3.134
1982 3.135
1983 3.123
1984 3.099
1985 3.063
1986 3.024
1987 3.014
1988 3.056
1989 3.14
1990 3.247
1991 3.342
1992 3.369
1993 3.289
1994 3.118
1995 2.909
1996 2.719
1997 2.593
1998 2.552
1999 2.592
2000 2.669
2001 2.744
2002 2.813
2003 2.884
2004 2.955
2005 3.024
2006 3.091
2007 3.142
2008 3.166
2009 3.166
2010 3.152
2011 3.137
2012 3.123
2013 3.112
2014 3.104
2015 3.097
2016 3.086
2017 3.07
2018 3.049
2019 3.023
2020 2.995
2021 2.967
2022 2.94
2023 2.917
2024 2.896
2025 2.876
2026 2.855
2027 2.834
2028 2.813
2029 2.792
2030 2.771
2031 2.749
2032 2.726
2033 2.702
2034 2.676
2035 2.649
2036 2.622
2037 2.594
2038 2.566
2039 2.537
2040 2.508
2041 2.479
2042 2.449
2043 2.419
2044 2.389
2045 2.359
2046 2.328
2047 2.299
2048 2.27
2049 2.242
2050 2.214
2051 2.187
2052 2.16
2053 2.134
2054 2.107
2055 2.082
2056 2.056
2057 2.03
2058 2.004
2059 1.978
2060 1.951
2061 1.925
2062 1.899
2063 1.873
2064 1.848
2065 1.823
2066 1.798
2067 1.772
2068 1.746
2069 1.72
2070 1.694
2071 1.668
2072 1.642
2073 1.616
2074 1.591
2075 1.565
2076 1.54
2077 1.515
2078 1.49
2079 1.465
2080 1.44
2081 1.416
2082 1.392
2083 1.368
2084 1.345
2085 1.322
2086 1.299
2087 1.276
2088 1.253
2089 1.23
2090 1.207
2091 1.184
2092 1.161
2093 1.138
2094 1.116
2095 1.093
2096 1.071
2097 1.049
2098 1.026
2099 1.004