Year	Number of
1990	136.25
1991	141.08
1992	145.95
1993	152.12
1994	158.79
1995	165.9
1996	172.89
1997	180.28
1998	188.9
1999	196.04
2000	205.24
2001	206.62
2002	212.76
2003	221.71
2004	231.75
2005	241.3
2006	250.22
2007	262.67
2008	274.15
2009	285.04
2010	294.63
2011	297.17
2012	300.14
2013	297.67
2014	297.06
2015	299.02
2016	304.95