Year	Number of
1990	140.24
1991	140.18
1992	146.58
1993	150.49
1994	157.82
1995	157.71
1996	159.93
1997	164.77
1998	171.63
1999	179.27
2000	189.8
2001	200.39
2002	211.55
2003	229.94
2004	239.87
2005	249.9
2006	255.63
2007	262.02
2008	264.87
2009	265.35
2010	265.15
2011	259.49
2012	267.39
2013	253.06
2014	252.71
2015	254.8
2016	254.14