Year	Number of
1990	143.75
1991	147.11
1992	152.45
1993	158.69
1994	164.55
1995	170.11
1996	179.71
1997	188.86
1998	198.14
1999	210.25
2000	221.75
2001	234.07
2002	247.29
2003	260.45
2004	274.69
2005	286.52
2006	298.39
2007	311.82
2008	325.23
2009	339.02
2010	354.49
2011	368.75
2012	382.69
2013	395.28
2014	409.7
2015	424.8
2016	443.88