Year	Number of
1990	288.88
1991	293.66
1992	296.74
1993	298.23
1994	299.16
1995	302.18
1996	308.95
1997	319.69
1998	326.58
1999	333.3
2000	340.86
2001	351.08
2002	362.42
2003	378.05
2004	392.56
2005	407.1
2006	423.61
2007	442.96
2008	461.3
2009	483.34
2010	501.74
2011	509.62
2012	518.08
2013	525.75
2014	529.91
2015	533.61
2016	538.46