Year	Number of
1990	7373.73
1991	7558.08
1992	7764.45
1993	7972
1994	8190.45
1995	8430.24
1996	8728.85
1997	9042.97
1998	9341.57
1999	9655.12
2000	10001.09
2001	10396.68
2002	10812.05
2003	11261.19
2004	11727.82
2005	12312.72
2006	12589.15
2007	12955
2008	13308.3
2009	13874.05
2010	14468.38
2011	15051.59
2012	15667.42
2013	16361.94
2014	17030.94
2015	17683.44
2016	18343.34