Year	Number of
1990	5176.64
1991	5474
1992	5790.32
1993	6143.94
1994	6528.03
1995	6946.51
1996	7376.6
1997	7836.13
1998	8353.89
1999	8909.05
2000	9520.93
2001	9994.94
2002	10501.19
2003	11077.04
2004	11672.94
2005	12288.97
2006	12876.11
2007	13486.21
2008	14146.16
2009	14842.18
2010	15577.43
2011	16281.63
2012	17009.3
2013	17760.25
2014	18546.69
2015	19363.02
2016	20187.11