Year	Number of
1990	206.83
1991	214.36
1992	222.95
1993	232.76
1994	243.99
1995	259.48
1996	270.24
1997	281.71
1998	294.05
1999	307.52
2000	324.72
2001	347.25
2002	369.69
2003	392
2004	416.59
2005	443.79
2006	458.64
2007	477.27
2008	498.12
2009	520.9
2010	543.55
2011	562.77
2012	571.62
2013	580.6
2014	589.73
2015	598.99
2016	608.95