Year	Number of
1990	140.99
1991	139.81
1992	137.76
1993	135.2
1994	132.64
1995	130.45
1996	132.54
1997	135.39
1998	139.09
1999	143.41
2000	148.23
2001	154.67
2002	161.87
2003	169.67
2004	177.77
2005	186.04
2006	193.36
2007	200.52
2008	207.77
2009	215.27
2010	223.32
2011	232.82
2012	243.21
2013	254.44
2014	266.48
2015	279.33
2016	293.79