Year	Number of
1990	163.17
1991	163.81
1992	164.22
1993	165.61
1994	169.48
1995	169.01
1996	175.3
1997	178.6
1998	180
1999	186.98
2000	192.09
2001	197.15
2002	203.7
2003	209.43
2004	217.4
2005	219.07
2006	223.42
2007	229.51
2008	236.67
2009	244.14
2010	250.77
2011	257.48
2012	262.71
2013	265.92
2014	271.92
2015	278.83
2016	286.16