Year	Number
1970	23000
1971	24200
1972	25200
1973	24000
1974	28000
1975	30000
1976	33000
1977	30100
1978	55000
1979	82300
1980	83700
1981	102200
1982	106400
1983	122900
1984	155000
1985	182800
1986	199700
1987	285400
1988	383700
1989	423800
1990	519700
1991	525300
1992	578100
1993	581900
1994	635900
1995	675800
1996	716900
1997	803900
1998	847500
1999	823200
2000	949085
2001	1002282
2002	1029466
2003	1042773
2004	1088696
2005	1145737
2006	1056496
2007	1277957
2008	1256746
2009	1092580
2010	1265458
2011	1321491
2012	1313976
2013	1318052
2014	1354388
2015	1466527
2016	1593666
2017	1674395
2018	1745291
2019	1726868
2020	407291
2021	153242