1949    3.2     565.5
1950    4.0     535.5
1951    3.4     460.6
1952    3.6     495.7
1953    4.4     979.0
1954    3.9     608.5
1955    3.6     642.0
1956    4.4     912.4
1957    4.2     635.6
1958    3.9     697.8
1959    4.2     945.0
1960    4.8     524.8
1961    4.2     637.6
1962    3.8     678.5
1963    3.7     558.8
1964    4.8     718.1
1965    3.9     561.9
1966    3.0     548.8
1967    3.0     659.3
1968    3.2     647.0
1969    2.6     877.2
1970    3.0     769.0
1971    3.2     726.1
1972    4.3     1028.8
1973    3.1     785.4
1974    4.3     865.9
1975    3.3     888.7
1976    4.0     903.1
1977    3.6     594.5
1978    3.8     619.3
1979    2.3     564.7
1980    3.8     580.9
1981    2.5     550.1
1982    3.2     574.9
1983    2.6     743.5
1984    3.6     673.9
1985    3.8     497.1
1986    3.5     618.0
1987    4.7     701.3
1988    3.3     735.0
1989    3.4     994.2
1990    3.9     858.2
1991    4.5     970.6
1992    3.9     1051.0
1993    3.8     959.2
1994    3.4     616.0
1995    3.0     589.9
1996    4.3     545.1
1997    4.1     613.3
1998    3.7     434.5
1999    3.8     528.8
2000    4.1     495.9
2001    4.3     680.2
2002    4.3     735.1
2003    5.4     790.2
2004    4.9     880.4
2005    4.3     594.5
2006    4.6     861.6
2007    4.8     1041.8
2008    4.7     901.8
2009    4.7     710.7
2010    5.3     459.0
2011    4.5     918.8
2012    5.0     672.2
2013    4.4     765.9
2014    5.3     678.8
2015    4.1     804.4
2016    5.5     806.2
2017    4.9     678.6
2018    4.5     875.3