Year	Number of
1990	137.61
1991	139.95
1992	142.47
1993	144.96
1994	147.73
1995	150.98
1996	152.74
1997	154.93
1998	157.14
1999	159.29
2000	161.41
2001	163.28
2002	165.07
2003	166.5
2004	167.99
2005	169.69
2006	173.84
2007	178.14
2008	182.79
2009	187.79
2010	193.21
2011	195.42
2012	197.92
2013	200.56
2014	203.42
2015	206.52
2016	210.28