Year	Number
1971	385628
1972	386496
1973	375004
1974	380728
1975	386559
1976	390129
1977	396194
1978	396672
1979	396132
1980	394510
1981	390186
1982	383599
1983	372705
1984	361581
1985	347316
1986	335373
1987	325577
1988	317228
1989	312384
1990	310600
1991	309432
1992	308516
1993	307461
1994	309889
1995	314062
1996	320752
1997	330619
1998	401652
1999	411878
2000	419805
2001	426475
2002	429445
2003	432618
2004	432345
2005	429652
2006	429680
2007	430747
2008	429585
2009	426769
2010	424052
2011	423333
2012	423351
2013	424993
2014	425917
2015	430864
2016	438387
2017	444638
2018	447355
2019	448655
2020	446218
2021	443967