Year	Number
1981	11000
1986	17900
1991	16514
1996	24086
1999	19234
2000	19284
2001	18783
2002	18860
2003	18376
2004	18341
2005	17729
2006	17781
2007	16824
2008	16524
2009	16332
2010	16089
2011	15691
2012	16959
2013	17072
2014	17175
2015	17226
2016	18770
2017	20110
2018	21154
2019	21484
2020	21919
2021	23012
2022	23249
2023	25366