Year	Number
1981	16944
1986	17992
1991	20473
1992	20281
1993	18400
1994	18275
1995	18022
1996	17950
1997	16542
1998	16841
1999	17365
2000	17714
2001	17732
2002	18406
2003	16500
2008	35860
2009	33511
2013	31595
2014	31428
2015	32001
2016	33020
2017	33398
2018	33998
2019	34555
2020	32616
2021	32677
2022	32737