Year	Number
1971	10542
1972	11220
1973	11939
1974	12442
1975	13687
1976	15149
1977	13077
1978	14079
1979	15064
1980	15621
1981	15986
1982	16039
1983	16871
1984	17480
1985	18307
1986	18773
1987	19500
1988	20183
1996	23536
1999	24871
2000	25369
2001	26012
2002	26452
2003	26558
2004	27319
2005	27581
2006	28089
2007	29273
2008	29802
2009	30311
2010	30474
2011	30828
2012	32490
2013	30926
2014	30574
2015	30405
2016	30063
2017	31007
2018	31106
2019	31050
2020	31437
2021	31760
2022	31676