Year	Number
1980	10259
1981	11378
1982	11373
1983	11542
1984	12178
1985	12132
1986	12349
1987	12611
1988	12431
1989	12901
1990	13278
1991	11762
1992	12100
1993	11284
1994	11647
1995	12277
1996	13221
1997	15398
1998	16063
1999	17960
2000	20073
2001	20548
2002	20181
2003	19176
2004	20274
2005	21302
2006	23166
2007	24122
2008	23525
2009	21187
2010	22478
2011	23143
2012	23731
2013	26656
2014	23968
2015	26314
2016	25774
2017	26403
2018	27200
2019	27121
2020	26926
2021	29443