1951	4.05
1952	73.6
1953	4.30
1954	3.90
1955	9.23
1956	3.68
1957	12.3
1958	2.29
1959	2.32
1960	2.32
1961	2.82
1962	37.1
1963	5.41
1964	7.59
1965	17.4
1966	3.96
1967	12.4
1968	5.61
1969	3.94
1970	6.94
1971	10.9
1972	885.0
1973	4.9
1974	14.6
1975	2.61
1976	18.0
1977	5.49
1978	12.3
1979	4.75
1980	3.37
1981	3.74
1982	7.48
1983	8.01
1984	7.05
1985	3.79
1986	2.52
1987	2.80
1988	3.57
1989	3.14
1990	3.51
1991	5.69
1992	2.97
1993	9.29
1994	5.61
1995	13.6
1996	18.5
1997	29.7
1998	14.2
1999	18.2
2000	5.41
2001	3.03
2002	3.94
2003	3.26
2004	2.83
2005	2.94
2006	3.31
2007	4.50