Year	Number of
1990	293.72
1991	289.35
1992	292.5
1993	293.47
1994	300.47
1995	293.97
1996	287.06
1997	286.31
1998	283.47
1999	294.19
2000	302.63
2001	314.31
2002	324.94
2003	336.89
2004	351.65
2005	365.28
2006	376.84
2007	385.43
2008	394.43
2009	402.35
2010	410.67
2011	419.7
2012	430.19
2013	442.64
2014	454.53
2015	468.09
2016	484.3