Year	Number of
1990	163.83
1991	171.82
1992	180.32
1993	189.38
1994	198.69
1995	207.58
1996	215.12
1997	223.22
1998	230.97
1999	240.17
2000	248.52
2001	257.96
2002	269.01
2003	279.76
2004	290.84
2005	302.12
2006	316.52
2007	331.68
2008	348.06
2009	365.46
2010	384.63
2011	400.72
2012	417.91
2013	435.54
2014	454.74
2015	475.81
2016	497.42