Year Percent
1950 1.992
1951 2
1952 2.032
1953 2.091
1954 2.166
1955 2.248
1956 2.326
1957 2.395
1958 2.448
1959 2.485
1960 2.511
1961 2.535
1962 2.568
1963 2.619
1964 2.684
1965 2.756
1966 2.821
1967 2.86
1968 2.857
1969 2.818
1970 2.759
1971 2.7
1972 2.666
1973 2.675
1974 2.721
1975 2.789
1976 2.854
1977 2.877
1978 2.835
1979 2.735
1980 2.615
1981 2.515
1982 2.463
1983 2.471
1984 2.537
1985 2.616
1986 2.681
1987 2.786
1988 2.979
1989 3.238
1990 3.532
1991 3.798
1992 3.907
1993 3.773
1994 3.436
1995 3.008
1996 2.616
1997 2.363
1998 2.306
1999 2.433
2000 2.647
2001 2.848
2002 3.003
2003 3.11
2004 3.168
2005 3.203
2006 3.241
2007 3.278
2008 3.305
2009 3.324
2010 3.335
2011 3.339
2012 3.336
2013 3.326
2014 3.31
2015 3.289
2016 3.266
2017 3.239
2018 3.207
2019 3.171
2020 3.133
2021 3.095
2022 3.058
2023 3.025
2024 2.995
2025 2.967
2026 2.937
2027 2.908
2028 2.879
2029 2.85
2030 2.821
2031 2.791
2032 2.761
2033 2.729
2034 2.696
2035 2.662
2036 2.627
2037 2.592
2038 2.555
2039 2.516
2040 2.477
2041 2.438
2042 2.399
2043 2.359
2044 2.32
2045 2.282
2046 2.243
2047 2.205
2048 2.167
2049 2.13
2050 2.094
2051 2.058
2052 2.023
2053 1.987
2054 1.952
2055 1.916
2056 1.881
2057 1.847
2058 1.814
2059 1.783
2060 1.752
2061 1.721
2062 1.689
2063 1.657
2064 1.625
2065 1.592
2066 1.559
2067 1.527
2068 1.495
2069 1.463
2070 1.431
2071 1.4
2072 1.369
2073 1.339
2074 1.309
2075 1.279
2076 1.25
2077 1.221
2078 1.191
2079 1.162
2080 1.132
2081 1.103
2082 1.074
2083 1.046
2084 1.018
2085 0.991
2086 0.965
2087 0.938
2088 0.912
2089 0.886
2090 0.86
2091 0.835
2092 0.81
2093 0.785
2094 0.761
2095 0.738
2096 0.715
2097 0.692
2098 0.669
2099 0.647