Year	Number of
1990	153.16
1991	155.8
1992	162.75
1993	167.08
1994	171.34
1995	177.29
1996	173.89
1997	176.35
1998	177.39
1999	181.71
2000	189.07
2001	199.93
2002	205.12
2003	210.96
2004	219.29
2005	227.65
2006	240.07
2007	247.96
2008	257.17
2009	266.1
2010	273.63
2011	286.36
2012	298.73
2013	313.04
2014	327.13
2015	342.62
2016	359.03