Year	Number
1971	15810
1972	16641
1975	18473
1976	20140
1977	20874
1978	21843
1979	22374
1980	22701
1982	23849
1983	24731
1984	24580
1985	24135
1986	28352
1987	27842
1988	27827
1989	27655
1990	26659
1991	25900
1992	25800
1993	25800
1994	27010
2002	43994
2003	46267
2004	48559
2005	48159
2006	48772
2007	50293
2008	52486
2009	52046
2010	52161
2011	55736
2012	55844
2015	58091.0390625
2016	58785.80859375
2017	60347.328125
2018	61663.5703125
2019	62504.8984375
2020	63699.58984375
2021	64333