Year	Number
1990	23306
1991	23000
1992	22710
1993	22336
1994	21793
1995	20954
1996	19930
1997	19175
1998	18870
1999	18907
2000	19245
2001	19846
2002	20528
2003	21112
2004	21566
2005	21854
2006	21918
2007	21734
2008	21250
2009	20627
2010	20116
2011	19937
2012	20105
2013	20543
2014	21069
2015	21480
2016	21682
2017	21836
2018	22077
2019	22687
2020	24126
2021	26548
2022	29141