Year	Number of
1990	228.53
1991	233.16
1992	238.01
1993	241.95
1994	248.43
1995	254.35
1996	260.09
1997	266.79
1998	276.29
1999	287.92
2000	300.5
2001	313.68
2002	327.18
2003	339.24
2004	358.68
2005	374.19
2006	389.29
2007	401.86
2008	412.71
2009	422.76
2010	431.01
2011	446.63
2012	462.91
2013	480.2
2014	498.25
2015	515.73
2016	535.12