Year	Number of
1990	100.89
1991	105.17
1992	112.08
1993	118.28
1994	128.76
1995	136.87
1996	144.93
1997	152.3
1998	161.6
1999	165.75
2000	167.72
2001	165.82
2002	164.94
2003	168.56
2004	173.99
2005	177.27
2006	185.7
2007	193.85
2008	203.02
2009	210.69
2010	219.17
2011	227.64
2012	234.35
2013	239.99
2014	248.03
2015	257.18
2016	266.56