Year	Number of
1990	110.2
1991	126.12
1992	143.25
1993	165.54
1994	188.36
1995	211.64
1996	220.89
1997	230.83
1998	232.73
1999	235.5
2000	238.58
2001	242.42
2002	245.82
2003	250.57
2004	255.58
2005	260.68
2006	264.94
2007	268.74
2008	273.45
2009	278.74
2010	284.74
2011	292.28
2012	300.81
2013	309.41
2014	319.43
2015	331.33
2016	348.31