Year	Number of
1990	254.89
1991	282.14
1992	311.22
1993	344.8
1994	377.7
1995	410.09
1996	414.04
1997	417.62
1998	414.47
1999	413.65
2000	413.07
2001	412.76
2002	411.98
2003	410.79
2004	408.95
2005	406.94
2006	404.74
2007	404.44
2008	405.79
2009	408.56
2010	411.63
2011	417.41
2012	424.47
2013	430.35
2014	438.89
2015	455.29
2016	475.61