Year	Number of
1990	134.6
1991	137.69
1992	142.18
1993	145.63
1994	151.6
1995	155.87
1996	160.29
1997	168.22
1998	178.97
1999	189.06
2000	200.31
2001	208.16
2002	216.97
2003	229.29
2004	241.03
2005	250.1
2006	257.53
2007	265.29
2008	274.38
2009	283.87
2010	296.86
2011	310.41
2012	322.44
2013	332.95
2014	345.52
2015	359.5
2016	373.13