Year	Number
1971	22003
1972	27255
1973	31288
1974	37546
1975	48415
1976	64404
1977	81169
1978	96065
1979	113730
1980	127894
1982	130366
1983	119106
1984	101989
1985	91207
1986	97120
1987	98490
1988	115390
1989	110318
1990	127704
1991	125545
1992	127831
1994	134559
1995	153348
1996	169481
1997	178254
1999	231948
2000	258677
2001	288347
2002	329307
2003	354965
2004	375385
2005	404470
2006	430064
2007	408964
2011	545861
2017	727949
2021	852361