Year	Number
1971	233617
1976	302178
1981	354102
1982	342102
1983	344305
1984	340443
1985	349951
1986	351433
1987	345418
1988	335971
1989	322961
1990	323988
1991	318986
1992	314389
1993	309165
1994	308091
1995	309883
1996	311633
1997	312519
1998	281188
1999	260902
2000	261722
2001	263081
2002	265645
2003	266909
2004	292161
2005	299968
2006	302683
2007	301168
2008	299903
2009	302047
2010	293980
2011	284644
2012	279253
2013	259553.075
2014	253505.5
2015	248659.91667
2016	241385.60758
2017	238160.67659