Year Percent
1950 2.81
1951 2.796
1952 2.765
1953 2.733
1954 2.71
1955 2.708
1956 2.733
1957 2.79
1958 2.871
1959 2.983
1960 3.099
1961 3.183
1962 3.213
1963 3.165
1964 3.045
1965 2.888
1966 2.728
1967 2.543
1968 2.303
1969 2.02
1970 1.721
1971 1.427
1972 1.172
1973 0.975
1974 0.832
1975 0.717
1976 0.611
1977 0.528
1978 0.491
1979 0.501
1980 0.536
1981 0.59
1982 0.621
1983 0.594
1984 0.517
1985 0.409
1986 0.306
1987 0.257
1988 0.304
1989 0.446
1990 0.637
1991 0.823
1992 0.945
1993 0.962
1994 0.874
1995 0.734
1996 0.596
1997 0.493
1998 0.45
1999 0.469
2000 0.518
2001 0.562
2002 0.593
2003 0.619
2004 0.634
2005 0.643
2006 0.651
2007 0.667
2008 0.692
2009 0.725
2010 0.762
2011 0.796
2012 0.817
2013 0.812
2014 0.781
2015 0.732
2016 0.687
2017 0.654
2018 0.625
2019 0.609
2020 0.602
2021 0.594
2022 0.589
2023 0.578
2024 0.565
2025 0.551
2026 0.537
2027 0.545
2028 0.577
2029 0.639
2030 0.716
2031 0.787
2032 0.842
2033 0.865
2034 0.86
2035 0.84
2036 0.818
2037 0.795
2038 0.771
2039 0.748
2040 0.725
2041 0.701
2042 0.669
2043 0.635
2044 0.601
2045 0.564
2046 0.529
2047 0.496
2048 0.466
2049 0.446
2050 0.429
2051 0.412
2052 0.398
2053 0.389
2054 0.381
2055 0.375
2056 0.371
2057 0.371
2058 0.373
2059 0.371
2060 0.372
2061 0.376
2062 0.376
2063 0.378
2064 0.377
2065 0.374
2066 0.373
2067 0.366
2068 0.36
2069 0.35
2070 0.336
2071 0.323
2072 0.308
2073 0.291
2074 0.272
2075 0.253
2076 0.233
2077 0.211
2078 0.19
2079 0.169
2080 0.146
2081 0.124
2082 0.104
2083 0.085
2084 0.067
2085 0.049
2086 0.031
2087 0.015
2088 0
2089 -0.015
2090 -0.027
2091 -0.042
2092 -0.056
2093 -0.068
2094 -0.078
2095 -0.088
2096 -0.099
2097 -0.109
2098 -0.116
2099 -0.125