Year	Number
1971	29683
1972	30835
1973	34628
1974	37998
1975	42668
1976	48488
1977	55485
1978	63769
1979	70625
1980	70514
1981	60065
1982	66669
1983	64148
1984	64562
1985	58075
1986	58445
1987	54964
1988	56618
1989	65832
1990	67337
1991	72788
1992	86065
1993	92866
1994	107105
1995	120997
1996	132861
1997	147959
1998	166372
1999	190916
2000	224733
2003	311717
2004	348749
2005	387520
2006	429554
2007	479156
2008	536745
2009	597039
2010	653619
2011	726754
2012	770323
2013	772481
2014	831931
2015	822679
2016	882472
2017	885112
2018	918775