Year	Number of
1990	483.75
1991	487.48
1992	490.95
1993	499.64
1994	495.82
1995	496.97
1996	496.94
1997	499.34
1998	503.75
1999	508.28
2000	511.78
2001	520.44
2002	523.32
2003	535.64
2004	548.16
2005	563.03
2006	569.98
2007	577.34
2008	585.66
2009	596
2010	608.77
2011	618.36
2012	630.39
2013	642.63
2014	656.37
2015	670.5
2016	685.69