Year	Number of
1990	172.28
1991	177.75
1992	184.44
1993	187.87
1994	197.75
1995	202.9
1996	210.26
1997	212.16
1998	209.81
1999	212.01
2000	217.13
2001	220.78
2002	221.11
2003	224.34
2004	231.18
2005	239.29
2006	244.75
2007	247.64
2008	247.09
2009	247.28
2010	252.73
2011	256.39
2012	268.12
2013	268.06
2014	273.45
2015	276.59
2016	279.77