Year	Years
1965	2.552
1966	2.875
1967	3.095
1968	3.944
1969	3.503
1970	3.465
1971	4.906
1972	5.334
1973	5.732
1974	5.935
1975	5.481
1976	5.919
1977	6.305
1978	6.256
1979	6.608
1980	6.895
1981	5.378
1982	4.976
1983	4.5
1984	4.434
1985	4.219
1986	3.236
1987	3.12
1988	3.264
1989	3.27
1990	3.289
1991	3.423
1992	3.842
1993	4.072
1994	4.251
1995	5.079
1996	5.935
1997	6.038
1998	5.212
1999	5.17
2000	5.117
2001	4.513
2002	4.025
2003	3.904