Year	Number
1970	5197
1971	6210
1972	7195
1973	10629
1974	12245
1975	14286
1976	16275
1977	17896
1978	18977
1979	19538
1980	20969
1981	22962
1983	25010
1984	30902
1985	36144
1986	39713
1987	42952
1988	44194
1989	53849
1990	61767
1991	77998
1992	80358
1993	90658
1994	91862
1995	111134
1998	153442
1999	157804
2000	163001
2001	163354
2002	166089
2003	167919
2004	171488
2005	173027
2006	176902
2007	178314
2008	168220
2021	175513