Year	Number
1990	17418
1991	17260
1992	17401
1993	17828
1994	18474
1995	19244
1996	19891
1997	20288
1998	20527
1999	20727
2000	20918
2001	21058
2002	21123
2003	21055
2004	20818
2005	20501
2006	20236
2007	20084
2008	19995
2009	19919
2010	19937
2011	20189
2012	20714
2013	21332
2014	21817
2015	21934
2016	21493
2017	20496
2018	19182
2019	17896
2020	16755
2021	15748
2022	14856