Year	Number of
1990	101.64
1991	107.02
1992	113.42
1993	122.41
1994	130.27
1995	137.82
1996	145.34
1997	149.74
1998	152.61
1999	151.93
2000	151.74
2001	152.04
2002	152.81
2003	155.14
2004	157.41
2005	161.76
2006	165.07
2007	165.46
2008	169.13
2009	172.36
2010	174.83
2011	176.65
2012	178.27
2013	185.69
2014	192.45
2015	200.06
2016	208.38