Year	Number
1971	31945
1972	34928
1973	40270
1974	42153
1975	44786
1976	50465
1977	64611
1978	72954
1979	82408
1980	85151
1981	90530
1982	101952
1983	107390
1984	119337
1985	126866
1986	140871
1987	150605
1988	157341
1989	158800
1990	155116
1991	167229
1992	188580
1993	219258
1994	248048
1995	269173
1996	289945
1997	312671
1998	330199
1999	346222
2000	355822
2001	360677
2002	375695
2003	394401
2004	434181
2005	443615
2006	465970
2007	483776
2008	473688
2009	512998
2010	531383
2011	535976
2012	553584
2013	568953
2014	592249
2015	632761
2016	601364
2017	616647
2018	655261
2019	677458
2020	654227