Year	Number of
1990	354.82
1991	359.27
1992	354.11
1993	356.12
1994	355.79
1995	355.34
1996	354.12
1997	351.32
1998	346.28
1999	339.88
2000	333.92
2001	335.01
2002	340.19
2003	338.55
2004	342.48
2005	342.74
2006	341.3
2007	343.2
2008	351.33
2009	360.59
2010	371.18
2011	384.01
2012	399.64
2013	412.42
2014	426.72
2015	442.44
2016	450.07