Year	Number of
1990	183.85
1991	181.28
1992	178.12
1993	175.58
1994	174.13
1995	169.86
1996	169.12
1997	168.76
1998	169.95
1999	174.42
2000	178.22
2001	182.65
2002	189.57
2003	197.26
2004	202.76
2005	207.52
2006	215.76
2007	225.03
2008	235.97
2009	246.19
2010	255.97
2011	262.58
2012	272.77
2013	277.93
2014	286.01
2015	294.86
2016	299.99