Year	Number
1971	17360
1972	17427
1973	19273
1974	21248
1975	23235
1976	24494
1977	27414
1978	25096
1979	25142
1980	24834
1981	25949
1982	26664
1983	24752
1984	25139
1996	23294
1997	21459
1998	21639
1999	22163
2000	23255
2001	24669
2002	25260
2003	24024
2004	24313
2005	24577
2006	24793
2007	24272
2008	24830
2009	25728
2010	24736
2011	25281
2012	25609
2013	26402
2014	26385
2016	26996
2017	26633
2018	27152
2019	27433
2020	28460
2021	27793
2022	28606