Year	Number
1971	62969
1972	73308
1973	83456
1974	86563
1975	95477
1976	102387
1977	112141
1978	125749
1979	144605
1980	172280
1981	198190
1982	213849
1983	217824
1984	229872
1985	245043
1986	260330
1987	257839
1988	272911
1989	303387
1990	333709
1991	361032
1992	396606
1993	414504
1994	445505
1995	463810
1996	489740
1997	527037
1998	539297
1999	565850
2000	599080
2001	639460
2002	703743
2006	762727
2007	808250
2008	851267
2009	929606
2011	999932
2012	1132464
2013	1215672
2014	1321556
2015	1478964
2016	1621874
2017	1791183
2018	1923876