Year Percent
1950 2.441
1951 2.597
1952 2.838
1953 2.958
1954 3.007
1955 3.027
1956 3.055
1957 3.121
1958 3.243
1959 3.419
1960 3.624
1961 3.814
1962 3.938
1963 3.964
1964 3.907
1965 3.81
1966 3.728
1967 3.725
1968 3.839
1969 4.052
1970 4.298
1971 4.51
1972 4.654
1973 4.72
1974 4.715
1975 4.673
1976 4.623
1977 4.572
1978 4.518
1979 4.46
1980 4.4
1981 4.333
1982 4.25
1983 4.144
1984 4.021
1985 3.886
1986 3.754
1987 3.649
1988 3.587
1989 3.562
1990 3.549
1991 3.522
1992 3.468
1993 3.38
1994 3.261
1995 3.136
1996 3.019
1997 2.881
1998 2.692
1999 2.463
2000 2.22
2001 1.997
2002 1.841
2003 1.785
2004 1.824
2005 1.912
2006 2.003
2007 2.091
2008 2.18
2009 2.264
2010 2.349
2011 2.433
2012 2.499
2013 2.532
2014 2.534
2015 2.52
2016 2.503
2017 2.49
2018 2.482
2019 2.479
2020 2.477
2021 2.472
2022 2.463
2023 2.452
2024 2.438
2025 2.423
2026 2.407
2027 2.392
2028 2.376
2029 2.362
2030 2.347
2031 2.331
2032 2.315
2033 2.298
2034 2.281
2035 2.263
2036 2.245
2037 2.226
2038 2.207
2039 2.188
2040 2.169
2041 2.149
2042 2.128
2043 2.107
2044 2.086
2045 2.065
2046 2.043
2047 2.021
2048 1.999
2049 1.975
2050 1.952
2051 1.928
2052 1.905
2053 1.883
2054 1.861
2055 1.839
2056 1.818
2057 1.796
2058 1.774
2059 1.751
2060 1.728
2061 1.705
2062 1.683
2063 1.66
2064 1.637
2065 1.615
2066 1.592
2067 1.57
2068 1.547
2069 1.524
2070 1.501
2071 1.479
2072 1.456
2073 1.434
2074 1.413
2075 1.392
2076 1.371
2077 1.35
2078 1.328
2079 1.307
2080 1.285
2081 1.264
2082 1.243
2083 1.222
2084 1.203
2085 1.183
2086 1.163
2087 1.144
2088 1.123
2089 1.102
2090 1.081
2091 1.06
2092 1.039
2093 1.019
2094 0.999
2095 0.98
2096 0.961
2097 0.941
2098 0.922
2099 0.903