Year	Number of
1990	191.52
1991	195.78
1992	190.53
1993	188.98
1994	184.08
1995	180.92
1996	176.69
1997	175.68
1998	175.17
1999	171.87
2000	165.1
2001	158.32
2002	151.54
2003	150.73
2004	147.94
2005	146.7
2006	141.44
2007	142.5
2008	140.23
2009	139.21
2010	138.88
2011	137.46
2012	137.39
2013	134.74
2014	129.34
2015	131.42
2016	132.37