Year	Number of
1990	266.79
1991	276.17
1992	282.63
1993	287.45
1994	292.24
1995	298.42
1996	313.01
1997	330.72
1998	350.77
1999	372.47
2000	395.28
2001	411.41
2002	428.18
2003	445.67
2004	464.24
2005	484.25
2006	489.9
2007	495.97
2008	503
2009	510.73
2010	519.33
2011	536.95
2012	556.59
2013	577.92
2014	600.28
2015	623.43
2016	648.71