Year	Years
1980	7.391
1981	7.237
1982	6.848
1983	6.322
1984	5.99
1985	5.085
1986	4.624
1987	4.883
1988	4.643
1989	4.295
1990	4.345
1991	3.75
1992	4.041
1993	4.064
1994	3.829
1995	4.247
1996	3.914
1997	2.677
1998	1.714
1999	1.036
2000	1.029
2001	1.337
2002	1.489
2003	2.453
2004	4.492