Year	Number of
1990	256.46
1991	264.53
1992	273.44
1993	282.77
1994	293.67
1995	306.28
1996	318.36
1997	330.63
1998	343.76
1999	356.52
2000	369.06
2001	381.92
2002	394.56
2003	411.18
2004	426.28
2005	440.6
2006	450.02
2007	458.42
2008	468.69
2009	481.4
2010	497.65
2011	522.91
2012	552.28
2013	581.85
2014	612.26
2015	643.5
2016	681.27