Year	Number of
1990	157.54
1991	166.07
1992	171.86
1993	177.05
1994	182.82
1995	188.7
1996	194.37
1997	200.3
1998	206.66
1999	212.32
2000	217.83
2001	222.39
2002	227.35
2003	232.92
2004	238.56
2005	244.07
2006	248.57
2007	252.95
2008	258.11
2009	264.18
2010	270.53
2011	276.05
2012	282.26
2013	288.92
2014	296.25
2015	304.05
2016	311.93