Year	Number of
1990	65.6
1991	70.51
1992	75.83
1993	81.66
1994	87.91
1995	94.63
1996	102.98
1997	112.03
1998	122.12
1999	133
2000	144.77
2001	149.27
2002	153.78
2003	158.68
2004	163.67
2005	168.73
2006	176.36
2007	184.12
2008	192.53
2009	201.2
2010	210.17
2011	218.24
2012	226.81
2013	236.03
2014	245.6
2015	255.48
2016	265.93