Year	Number of
1990	12959.64
1991	13196.14
1992	13644.05
1993	13858.07
1994	14186.13
1995	14604.59
1996	14877.43
1997	15289.91
1998	15695.22
1999	16127.23
2000	16300.74
2001	16396.63
2002	16496.12
2003	16697.76
2004	16905.65
2005	17055.85
2006	17224.34
2007	17452.81
2008	17669
2009	17968.9
2010	18217.03
2011	18438.98
2012	18692.23
2013	18873.25
2014	19173.75
2015	19471.13
2016	19574.19