Year	Number of
1990	337.45
1991	332.97
1992	327.37
1993	318.5
1994	309.61
1995	296.91
1996	286.28
1997	275.72
1998	263.5
1999	255.38
2000	237.63
2001	230.93
2002	224.13
2003	219.94
2004	213.39
2005	207.54
2006	200.9
2007	199.29
2008	192.65
2009	188.08
2010	184.14
2011	178.94
2012	177.29
2013	176.42
2014	175.44
2015	174.02
2016	173.91