Year	Number of
1990	73.55
1991	76.45
1992	79.71
1993	83.32
1994	86.98
1995	90.86
1996	93.61
1997	96.44
1998	99.38
1999	102.73
2000	105.28
2001	111.16
2002	116.76
2003	122.64
2004	129.25
2005	131.61
2006	135.96
2007	140.98
2008	146.71
2009	152.65
2010	158.94
2011	165.24
2012	171.99
2013	179.41
2014	187.41
2015	196.11
2016	204.65