Year	Number of
1990	176
1991	179.64
1992	182.81
1993	185.21
1994	188.69
1995	193.85
1996	205.05
1997	218.54
1998	234
1999	250.12
2000	266.36
2001	280.15
2002	293.95
2003	309.38
2004	326.13
2005	344.68
2006	358.35
2007	373.02
2008	388.84
2009	405.45
2010	422.89
2011	431.55
2012	440.34
2013	449.31
2014	459.04
2015	469.73
2016	480.37