Year	Number
1970	29000
1971	27500
1972	25200
1973	25700
1974	27500
1975	25800
1976	27100
1977	27400
1978	27700
1979	31100
1980	28400
1981	27700
1982	26600
1983	26300
1984	30800
1985	32500
1986	33500
1987	36600
1988	61400
1989	73000
1990	79500
1991	82400
1992	76700
1993	69000
1994	70300
1995	84000
1996	95000
1997	107200
1998	122700
1999	132700
2000	145457
2001	156277
2002	177032
2003	231296
2004	261345
2005	303697
2006	350204
2007	416205
2008	483741
2009	528098
2010	601262
2011	635065
2012	648817.651510641
2013	641412
2014	658512
2015	718059
2016	836293
2017	883323
2018	935913
2019	967456
2020	369019
2021	493773