Year	Number of
1990	79.51
1991	79.91
1992	81.13
1993	81.42
1994	82.76
1995	85.74
1996	85.94
1997	86.15
1998	86.63
1999	85.04
2000	85.88
2001	86.38
2002	86.44
2003	87.41
2004	88.18
2005	90.05
2006	91.44
2007	93.85
2008	96.53
2009	99.22
2010	100.65
2011	102.82
2012	105.19
2013	107.81
2014	110.81
2015	113.86
2016	116.47