Year	Number of
1990	321
1991	317.32
1992	317.49
1993	319.69
1994	322.03
1995	330.48
1996	337.68
1997	346.12
1998	371.05
1999	400.18
2000	431.36
2001	450.05
2002	473.47
2003	485.47
2004	503.6
2005	504.99
2006	508.72
2007	509.49
2008	517.37
2009	531.51
2010	534.88
2011	538.38
2012	546.07
2013	555.42
2014	583.1
2015	599.61
2016	617.99