Year	Number of
1990	271.09
1991	280.26
1992	290.2
1993	305.21
1994	321.05
1995	342.07
1996	363.73
1997	373.61
1998	391.97
1999	402.17
2000	417.98
2001	429.44
2002	441.68
2003	462.52
2004	468.69
2005	482.44
2006	501.5
2007	512.25
2008	530.96
2009	551.05
2010	570.87
2011	580.91
2012	603.68
2013	617.95
2014	628.06
2015	633.68
2016	643.64