Year	Number
1980	183223
1981	169851
1982	173167
1983	170240
1984	185407
1985	259055
1986	290459
1987	333532
1988	384924
1989	413321
1990	426656
1991	405101
1992	410556
1993	466483
1994	487422
1995	519055
1996	465402
1997	495011
1998	547876
1999	579665
2000	662656
2001	568099
2002	524348
2003	525518
2004	522983
2005	527448
2006	523144
2007	533164
2008	503838
2009	443420
2010	464226
2011	457341
2012	438177
2013	447818
2014	459009
2015	463838
2016	477220
2017	493563