Year	Number of
1990	113.7
1991	121.35
1992	128.69
1993	136.64
1994	140.69
1995	142.05
1996	140.13
1997	149.44
1998	154.84
1999	168.19
2000	173.57
2001	182.33
2002	187.83
2003	195.98
2004	202.93
2005	206.3
2006	204.31
2007	205.53
2008	206.61
2009	208.18
2010	207.56
2011	209.2
2012	207.04
2013	212.75
2014	218.56
2015	229.16
2016	237.57