Year	Number of
1990	198.61
1991	196.7
1992	193.84
1993	191.16
1994	189.98
1995	191.18
1996	194.03
1997	200.19
1998	208.65
1999	217.79
2000	226.88
2001	233.44
2002	240.12
2003	247.28
2004	255.24
2005	264.33
2006	275.12
2007	286.92
2008	300.12
2009	314.4
2010	329.79
2011	347.49
2012	366.75
2013	387.06
2014	407.79
2015	428.61
2016	447.62