Year	Number of
1990	247.31
1991	254.33
1992	262.29
1993	271.01
1994	280.3
1995	290.36
1996	300.93
1997	312.21
1998	323.79
1999	336.7
2000	351.42
2001	360.89
2002	371.39
2003	381.64
2004	392.58
2005	404.39
2006	405.32
2007	405.58
2008	406.92
2009	409.25
2010	413.17
2011	426.65
2012	442.34
2013	460.47
2014	479.88
2015	500.34
2016	523.78