Year	Number of
1990	205.74
1991	210.77
1992	217.19
1993	226.27
1994	228.44
1995	235
1996	240.37
1997	248.28
1998	254.56
1999	258.06
2000	265.4
2001	270.4
2002	280.72
2003	290.26
2004	299.84
2005	305.44
2006	313.11
2007	322.33
2008	336.08
2009	351.3
2010	367.17
2011	380.69
2012	395.24
2013	410.02
2014	425.51
2015	442.36
2016	459.24