Year	Number of
1990	142.26
1991	143.46
1992	143.22
1993	139.74
1994	139.12
1995	140.24
1996	152.41
1997	165.92
1998	176.96
1999	173.72
2000	168.17
2001	157.93
2002	154.08
2003	148.06
2004	144.84
2005	141.9
2006	142.9
2007	143.08
2008	141.5
2009	140.19
2010	139.44
2011	138.78
2012	139.2
2013	141.91
2014	145.26
2015	149.55
2016	154.44