Year	Number of
1990	146
1991	150.87
1992	156.21
1993	162.09
1994	167.97
1995	173.68
1996	180.5
1997	186.99
1998	193.69
1999	200.48
2000	207.68
2001	219.47
2002	232.64
2003	248.61
2004	265.47
2005	283
2006	295.66
2007	308.34
2008	321.93
2009	337.39
2010	355.26
2011	369.19
2012	384.6
2013	400.11
2014	416.21
2015	432.76
2016	451.94