Year	Number of
1990	169.74
1991	169.62
1992	171.76
1993	173.66
1994	177.01
1995	177
1996	175.01
1997	174.75
1998	174.05
1999	177.62
2000	179.2
2001	181.82
2002	184.13
2003	187.33
2004	190.61
2005	194.25
2006	201.5
2007	208.89
2008	216.92
2009	225.49
2010	234.87
2011	244.15
2012	254.3
2013	265.43
2014	277.47
2015	291.1
2016	305.47