Year	Number of
1990	157.28
1991	164.5
1992	173.26
1993	184.65
1994	195.57
1995	210.43
1996	227.22
1997	250.85
1998	270.15
1999	294.25
2000	316.59
2001	334.85
2002	353.38
2003	374.04
2004	391.98
2005	413.25
2006	428.28
2007	442.19
2008	459.68
2009	479.55
2010	498
2011	514.16
2012	533.44
2013	555.98
2014	575.92
2015	590.07
2016	606.17