Year	Number of
1990	215.44
1991	218.18
1992	221.88
1993	225.95
1994	230.28
1995	234.81
1996	238.59
1997	242.49
1998	246.92
1999	251.64
2000	256.82
2001	264.15
2002	272.12
2003	281.03
2004	290.58
2005	300.95
2006	311.68
2007	322.95
2008	335.11
2009	348.06
2010	361.95
2011	376.47
2012	391.96
2013	407.9
2014	425.14
2015	443.83
2016	465