Year	Number
1992	12971
1993	13500
1994	14359
1995	15460
1996	18837
1997	20639
1998	20639
1999	20528
2000	20990
2001	21400
2002	21900
2003	22400
2004	22800
2005	23300
2006	23800
2007	24200
2008	24700
2009	25100
2010	25500
2012	23000
2013	23000
2014	22400
2015	22000
2019	20000
2020	20000
2021	20000