Year	Number of
1990	255.61
1991	256.9
1992	261.54
1993	273.13
1994	285.64
1995	299.51
1996	309.79
1997	323.91
1998	323.25
1999	319.69
2000	320.31
2001	330.4
2002	343.59
2003	358.46
2004	375.83
2005	389.59
2006	403.77
2007	419.52
2008	436.9
2009	455.82
2010	476.73
2011	496.61
2012	520.06
2013	535.77
2014	552.78
2015	565.12
2016	582.31