Year	Number of
1990	99.31
1991	96.46
1992	93.71
1993	90.79
1994	88.08
1995	85.58
1996	83.76
1997	81.87
1998	80.22
1999	78.73
2000	77.42
2001	78.28
2002	79.25
2003	80.92
2004	82.66
2005	84.61
2006	86.37
2007	88.22
2008	90.02
2009	92
2010	94.17
2011	95.66
2012	97.52
2013	99.35
2014	101.5
2015	103.97
2016	107.27