Year Percent
1950 2.597
1951 2.612
1952 2.643
1953 2.675
1954 2.707
1955 2.741
1956 2.775
1957 2.811
1958 2.847
1959 2.883
1960 2.92
1961 2.957
1962 2.993
1963 3.029
1964 3.064
1965 3.099
1966 3.135
1967 3.169
1968 3.198
1969 3.223
1970 3.243
1971 3.261
1972 3.29
1973 3.341
1974 3.408
1975 3.479
1976 3.538
1977 3.574
1978 3.581
1979 3.56
1980 3.532
1981 3.509
1982 3.472
1983 3.402
1984 3.31
1985 3.195
1986 3.077
1987 3.029
1988 3.106
1989 3.285
1990 3.514
1991 3.715
1992 3.783
1993 3.656
1994 3.361
1995 2.989
1996 2.641
1997 2.397
1998 2.301
1999 2.342
2000 2.453
2001 2.556
2002 2.599
2003 2.56
2004 2.446
2005 2.3
2006 2.169
2007 2.089
2008 2.075
2009 2.125
2010 2.204
2011 2.28
2012 2.337
2013 2.371
2014 2.382
2015 2.381
2016 2.382
2017 2.384
2018 2.386
2019 2.387
2020 2.386
2021 2.383
2022 2.374
2023 2.359
2024 2.339
2025 2.315
2026 2.29
2027 2.265
2028 2.24
2029 2.216
2030 2.192
2031 2.167
2032 2.141
2033 2.114
2034 2.086
2035 2.057
2036 2.028
2037 1.999
2038 1.97
2039 1.94
2040 1.909
2041 1.88
2042 1.85
2043 1.822
2044 1.793
2045 1.766
2046 1.739
2047 1.712
2048 1.687
2049 1.662
2050 1.638
2051 1.614
2052 1.591
2053 1.568
2054 1.545
2055 1.523
2056 1.501
2057 1.479
2058 1.457
2059 1.435
2060 1.414
2061 1.392
2062 1.37
2063 1.348
2064 1.326
2065 1.304
2066 1.281
2067 1.258
2068 1.235
2069 1.211
2070 1.187
2071 1.163
2072 1.14
2073 1.116
2074 1.092
2075 1.069
2076 1.046
2077 1.023
2078 1.001
2079 0.98
2080 0.959
2081 0.939
2082 0.919
2083 0.899
2084 0.88
2085 0.862
2086 0.845
2087 0.827
2088 0.809
2089 0.791
2090 0.773
2091 0.756
2092 0.739
2093 0.722
2094 0.706
2095 0.69
2096 0.674
2097 0.659
2098 0.643
2099 0.628