Year	Number
1971	67038
1972	75247
1973	82505
1974	88719
1975	95870
1976	106891
1977	130405
1978	142521
1979	154277
1980	167253
1981	181461
1982	195741
1983	208589
1984	219758
1985	229738
1986	238420
1987	244843
1988	255722
1989	264138
1990	270580
1991	140324
1992	166697
1993	176572
1994	186839
1995	197326
1996	204959
1997	214001
1998	223035
1999	231115
2000	235852
2001	239520
2002	239047
2003	247103
2004	251553
2005	234073
2006	231236
2007	242631
2008	246100
2009	250745
2010	258184
2011	262378
2012	269487
2013	272380
2014	276911
2015	294772
2016	308174
2017	317907
2018	324426