1964	1.14	
1965	1.02	
1966	0.94	
1967	1.25	
1968	1.13	
1969	1.52	
1970	1.43	
1971	2.16	
1972	2.52	
1973	1.74	
1974	1.11	
1975	1.23	
1976	1.44	
1977	1.74	
1978	2.53	
1979	1.9	
1980	1.9	
1981	1.83	
1982	1.49	
1983	0.97	
1984	1.15	
1985	1.37	
1986	1.51	
1987	1.81	
1988	2.14	
1989	2.13	
1990	1.91	
1991	1.61	
1992	0.99	
1993	0.8	
1994	0.76	
1995	1.15	
1996	1.15	
1994  0.54
1995  0.82
1996  0.84
1997	0.92
1998	1.24
1999	1.37
2000	1.22
2001	0.94
2002	0.79
2003	0.78
2004	0.67