Year	Number of
1990	267.04
1991	277.38
1992	288.45
1993	300.12
1994	312.15
1995	324.68
1996	330.26
1997	336.19
1998	342.58
1999	349.37
2000	356.86
2001	378.92
2002	403.02
2003	429.33
2004	457.76
2005	488.75
2006	496.12
2007	504.08
2008	513.43
2009	523.55
2010	534.7
2011	544.21
2012	554.94
2013	566.3
2014	578.81
2015	592.47
2016	606.15