Year	Number
1971	24388
1972	28137
1973	28231
1974	28434
1975	31736
1976	32409
1977	30285
1978	28921
1979	27302
1980	27673
1981	25501
1982	26700
1983	27257
1984	27901
1985	27899
1986	27779
1987	27858
1988	28806
1989	30210
1990	31837
1991	32544
1992	34358
1993	34619
1994	34955
1995	35527
1996	35044
1997	35451
1998	35682
1999	35457
2000	36074
2001	36158
2002	36236
2003	36978
2004	41353
2005	40129
2006	38335
2007	38499
2008	37774
2010	37163
2011	32227
2012	31768
2013	30989
2014	30230
2015	29434
2016	28776
2017	30760
2018	30925
2019	30727.8203125
2020	30971.892578125
2021	31333.5
2022	31394.900390625