Year	Number
1986	41936
1989	36140
1990	39343
1991	36449
1992	34395
1993	29613
1994	28114
1995	27806
1996	16946
1998	19345
1999	18896
2000	18092
2001	17714
2002	18132
2003	16544
2004	17396
2005	19153
2006	18912
2007	19173
2008	18761
2009	18687
2010	18686
2011	17832
2012	16449
2013	15539
2014	14621
2015	14989
2016	17176
2017	19102