Year Percent
1950 2.653
1951 2.688
1952 2.751
1953 2.804
1954 2.851
1955 2.892
1956 2.932
1957 2.97
1958 3.009
1959 3.049
1960 3.089
1961 3.129
1962 3.168
1963 3.205
1964 3.239
1965 3.273
1966 3.306
1967 3.346
1968 3.394
1969 3.45
1970 3.508
1971 3.561
1972 3.608
1973 3.647
1974 3.679
1975 3.703
1976 3.72
1977 3.737
1978 3.76
1979 3.785
1980 3.806
1981 3.817
1982 3.809
1983 3.778
1984 3.728
1985 3.666
1986 3.602
1987 3.535
1988 3.461
1989 3.383
1990 3.305
1991 3.229
1992 3.154
1993 3.077
1994 3
1995 2.925
1996 2.856
1997 2.801
1998 2.765
1999 2.746
2000 2.736
2001 2.728
2002 2.723
2003 2.726
2004 2.733
2005 2.742
2006 2.749
2007 2.752
2008 2.747
2009 2.736
2010 2.72
2011 2.702
2012 2.681
2013 2.652
2014 2.618
2015 2.58
2016 2.542
2017 2.505
2018 2.468
2019 2.433
2020 2.399
2021 2.364
2022 2.331
2023 2.3
2024 2.272
2025 2.245
2026 2.217
2027 2.189
2028 2.16
2029 2.131
2030 2.101
2031 2.07
2032 2.04
2033 2.007
2034 1.974
2035 1.94
2036 1.907
2037 1.873
2038 1.838
2039 1.804
2040 1.769
2041 1.735
2042 1.701
2043 1.668
2044 1.637
2045 1.606
2046 1.576
2047 1.545
2048 1.515
2049 1.486
2050 1.456
2051 1.427
2052 1.398
2053 1.369
2054 1.339
2055 1.31
2056 1.281
2057 1.253
2058 1.224
2059 1.196
2060 1.168
2061 1.14
2062 1.112
2063 1.084
2064 1.056
2065 1.029
2066 1.001
2067 0.974
2068 0.946
2069 0.919
2070 0.892
2071 0.865
2072 0.838
2073 0.812
2074 0.787
2075 0.762
2076 0.737
2077 0.713
2078 0.69
2079 0.667
2080 0.645
2081 0.623
2082 0.601
2083 0.579
2084 0.557
2085 0.535
2086 0.514
2087 0.493
2088 0.472
2089 0.452
2090 0.432
2091 0.413
2092 0.394
2093 0.375
2094 0.356
2095 0.338
2096 0.32
2097 0.302
2098 0.285
2099 0.269