Year	Number of
1990	252.01
1991	255.85
1992	260.13
1993	264.43
1994	270.01
1995	275.79
1996	281.02
1997	287.07
1998	296.89
1999	310.08
2000	323.9
2001	344.24
2002	367.54
2003	397.91
2004	415.95
2005	440.5
2006	457.01
2007	476.19
2008	494.82
2009	519.26
2010	547.69
2011	575.26
2012	602.31
2013	630.54
2014	659.13
2015	687.54
2016	720.54