Year	Number of
1990	125.06
1991	129.23
1992	132.41
1993	136.16
1994	140.51
1995	143
1996	145.42
1997	150.86
1998	153.55
1999	149.87
2000	149.35
2001	147.9
2002	148.15
2003	150.28
2004	149.05
2005	152.06
2006	153.11
2007	158.55
2008	162.4
2009	166.36
2010	171.46
2011	177.94
2012	184.63
2013	191.39
2014	198.34
2015	204.94
2016	212.27