Year Percent
1950 2.538
1951 2.654
1952 2.829
1953 2.928
1954 2.956
1955 2.945
1956 2.935
1957 2.934
1958 2.957
1959 3.005
1960 3.075
1961 3.126
1962 3.134
1963 3.09
1964 2.999
1965 2.883
1966 2.771
1967 2.713
1968 2.737
1969 2.841
1970 2.973
1971 3.085
1972 3.16
1973 3.185
1974 3.155
1975 3.12
1976 3.082
1977 3.014
1978 2.907
1979 2.757
1980 2.596
1981 2.448
1982 2.335
1983 2.277
1984 2.273
1985 2.286
1986 2.292
1987 2.323
1988 2.411
1989 2.542
1990 2.701
1991 2.853
1992 2.91
1993 2.807
1994 2.568
1995 2.26
1996 1.971
1997 1.794
1998 1.781
1999 1.924
2000 2.144
2001 2.347
2002 2.492
2003 2.559
2004 2.549
2005 2.506
2006 2.466
2007 2.434
2008 2.404
2009 2.374
2010 2.346
2011 2.313
2012 2.277
2013 2.245
2014 2.214
2015 2.183
2016 2.153
2017 2.121
2018 2.087
2019 2.052
2020 2.017
2021 1.983
2022 1.948
2023 1.916
2024 1.885
2025 1.854
2026 1.825
2027 1.797
2028 1.77
2029 1.743
2030 1.719
2031 1.694
2032 1.67
2033 1.644
2034 1.617
2035 1.593
2036 1.567
2037 1.541
2038 1.516
2039 1.491
2040 1.466
2041 1.44
2042 1.415
2043 1.39
2044 1.365
2045 1.341
2046 1.314
2047 1.289
2048 1.265
2049 1.24
2050 1.215
2051 1.19
2052 1.165
2053 1.142
2054 1.119
2055 1.096
2056 1.073
2057 1.051
2058 1.028
2059 1.006
2060 0.983
2061 0.961
2062 0.939
2063 0.918
2064 0.898
2065 0.877
2066 0.856
2067 0.836
2068 0.817
2069 0.797
2070 0.776
2071 0.756
2072 0.737
2073 0.717
2074 0.699
2075 0.68
2076 0.662
2077 0.645
2078 0.627
2079 0.61
2080 0.594
2081 0.577
2082 0.559
2083 0.543
2084 0.526
2085 0.511
2086 0.495
2087 0.478
2088 0.462
2089 0.446
2090 0.429
2091 0.413
2092 0.398
2093 0.382
2094 0.366
2095 0.35
2096 0.335
2097 0.32
2098 0.304
2099 0.288