year y
1947 3.9
1948 3.8
1949 5.9
1950 5.3
1951 3.3
1952 3.0
1953 2.9
1954 5.5
1955 4.4
1956 4.1
1957 4.3
1958 6.8
1959 5.5
1960 5.5
1961 6.7
1962 5.5
1963 5.7
1964 5.2
1965 4.5
1966 3.8
1967 3.8
1968 3.6
1969 3.5
1970 4.9
1971 5.9
1972 5.6
1973 4.9
1974 5.6
1975 8.5
1976 7.7
1977 7.1
1978 6.1
1979 5.8
1980 7.1
1981 7.6
1982 9.7
1983 9.6
1984 7.5
1985 7.2
1986 7.0
1987 6.2
1988 5.5
1989 5.3
1990 5.6
1991 6.8
1992 7.5
1993 6.9
1994 6.1
1995 5.6
1996 5.4
1997 4.9
1998 4.5
1999 4.2
2000 4.0
2001 4.7
2002 5.8
2003 6.0
2004 5.5
2005 5.1
2006 4.6
2007 4.6
2008 5.8
2009 9.3
2010 9.6
2011 8.9
2012 8.1
2013 7.4
2014 6.2
2015 5.3
2016 4.9
