Year	Number
1970	278174
1971	290874
1972	288878
1973	285185
1974	275846
1975	264659
1976	257976
1977	255711
1978	266048
1979	273392
1980	271456
1981	262655
1982	251138
1983	253818
1984	254360
1985	250059
1986	261144
1987	269691
1988	281408
1989	298893
1990	326019
1991	334351
1992	350734
1993	355606
1994	346278
1995	351680
1996	351044
1997	353874
1998	348801
1999	349470
2000	312532
2001	299581
2002	288634
2003	284683
2004	282685
2005	279678
2006	264411
2007	262812
2008	265436
2009	261619
2010	250302
2011	235923
2012	236664
2013	241077
2014	243770
2015	242886
2016	243933
2017	235628
2018	247425