Year	Number of
1990	122.96
1991	125.5
1992	131.29
1993	138.92
1994	147.45
1995	155.88
1996	158.83
1997	161.38
1998	163.35
1999	167.42
2000	171.52
2001	177.93
2002	186.05
2003	200.75
2004	221.2
2005	237.52
2006	256.56
2007	272.32
2008	296.07
2009	318.53
2010	339.45
2011	353.34
2012	364.54
2013	375.47
2014	388.42
2015	402.15
2016	416.43