Year	Number
1971	1662
1972	2381
1973	2174
1974	2285
1975	2435
1976	2498
1977	2467
1979	2291
1980	2229
1981	2141
1982	2180
1983	2253
1984	2032
1985	2176
1986	2315
1987	2360
1988	2452
1989	2509
1990	2604
1991	2688
1992	2673
1993	2710
1994	2989
1995	3135
1996	3038
1997	3076
1998	3173
1999	3253
2000	3371
2001	3476
2002	3450
2003	3662
2004	3567
2005	3499
2006	3392
2007	3551
2008	3550
2011	3876
2012	3728
2013	3826
2014	3841
2015	3775.6591796875
2016	3991
2017	4324.7998046875
2019	4370.505859375
2020	4532
2021	4612.703125