Year	Number of
1990	62.12
1991	64.22
1992	66.55
1993	69.08
1994	71.79
1995	74.77
1996	75.93
1997	77.28
1998	78.78
1999	80.45
2000	82.36
2001	82.75
2002	83.36
2003	84.09
2004	84.93
2005	85.9
2006	86.93
2007	87.92
2008	89.09
2009	90.36
2010	91.84
2011	93.4
2012	95.19
2013	97.09
2014	99.14
2015	101.34
2016	103.48