Year	Number of
1990	324.55
1991	331.29
1992	337.99
1993	343.99
1994	350.59
1995	358.15
1996	366.14
1997	376.59
1998	384.02
1999	389.92
2000	394.39
2001	401.89
2002	408.43
2003	414.69
2004	420.93
2005	426.25
2006	429.22
2007	435.11
2008	436.85
2009	435.9
2010	437.69
2011	450.05
2012	463.09
2013	480.4
2014	499.91
2015	521.64
2016	546.7