Year	Number
1970	500
1975	21000
1976	39580
1977	52000
1978	52000
1979	52000
1980	52000
1981	167000
1982	167000
1983	167000
1984	167000
1985	174160
1986	167220
1987	167000
1988	170000
1989	169103
1990	169110
1991	169124
1992	219314
1993	219067
1994	219073
1995	192489
1996	190267
1997	170736
1998	165226
1999	165249
2000	169654
2001	169417
2002	169233
2003	169032
2004	169053
2005	94104
2006	94181
2007	94137
2008	94094
2009	94136
2010	94141
2011	94145
2012	94130
2013	94142
2014	94119
2015	94176
2016	94220
2017	94248
2018	94341
2019	98599
2020	97651
2021	97890
2022	99107
2023	98590