Year Percent
1950 2.393
1951 2.434
1952 2.514
1953 2.587
1954 2.65
1955 2.701
1956 2.739
1957 2.761
1958 2.769
1959 2.762
1960 2.745
1961 2.721
1962 2.695
1963 2.672
1964 2.652
1965 2.634
1966 2.615
1967 2.582
1968 2.522
1969 2.44
1970 2.35
1971 2.269
1972 2.215
1973 2.198
1974 2.217
1975 2.254
1976 2.293
1977 2.334
1978 2.381
1979 2.433
1980 2.481
1981 2.521
1982 2.563
1983 2.614
1984 2.67
1985 2.726
1986 2.771
1987 2.77
1988 2.696
1989 2.559
1990 2.393
1991 2.234
1992 2.102
1993 2.008
1994 1.951
1995 1.913
1996 1.877
1997 1.848
1998 1.837
1999 1.842
2000 1.859
2001 1.884
2002 1.897
2003 1.887
2004 1.855
2005 1.809
2006 1.765
2007 1.757
2008 1.807
2009 1.911
2010 2.039
2011 2.156
2012 2.226
2013 2.227
2014 2.163
2015 2.068
2016 1.973
2017 1.89
2018 1.82
2019 1.763
2020 1.712
2021 1.66
2022 1.609
2023 1.565
2024 1.528
2025 1.494
2026 1.463
2027 1.437
2028 1.418
2029 1.404
2030 1.394
2031 1.385
2032 1.377
2033 1.37
2034 1.364
2035 1.358
2036 1.351
2037 1.34
2038 1.323
2039 1.301
2040 1.275
2041 1.248
2042 1.22
2043 1.191
2044 1.161
2045 1.129
2046 1.098
2047 1.066
2048 1.036
2049 1.005
2050 0.976
2051 0.947
2052 0.919
2053 0.892
2054 0.867
2055 0.843
2056 0.819
2057 0.797
2058 0.777
2059 0.759
2060 0.742
2061 0.726
2062 0.709
2063 0.693
2064 0.676
2065 0.66
2066 0.644
2067 0.628
2068 0.612
2069 0.596
2070 0.58
2071 0.564
2072 0.548
2073 0.533
2074 0.517
2075 0.502
2076 0.487
2077 0.472
2078 0.458
2079 0.443
2080 0.429
2081 0.415
2082 0.402
2083 0.388
2084 0.374
2085 0.361
2086 0.347
2087 0.334
2088 0.32
2089 0.305
2090 0.291
2091 0.276
2092 0.262
2093 0.247
2094 0.232
2095 0.217
2096 0.202
2097 0.186
2098 0.17
2099 0.154