Year	Number
1971	9553
1972	7362
1973	7279
1974	6873
1975	6425
1976	17303
1977	18518
1978	25600
1979	30092
1980	16758
1981	10106
1982	16102
1983	20095
1984	24029
1985	26522
1986	74103
1987	77500
1988	83089
1989	87889
1990	88180
1991	87704
1992	83756
1993	83266
1994	90184
1995	95568
1996	96974
1997	96460
1998	101002
1999	103448
2000	100112
2001	104745
2002	99319
2003	106097
2004	114698
2005	113240
2006	118515
2007	120133
2008	127179
2009	140864
2010	146805
2011	149948
2012	155414
2017	228179
2018	246199