Year	Number of
1990	212.12
1991	220.98
1992	232.74
1993	249.78
1994	266.13
1995	280.79
1996	293.83
1997	306.81
1998	318.7
1999	329.69
2000	338.94
2001	347.66
2002	357.05
2003	368.22
2004	380.6
2005	393.11
2006	404.92
2007	418.82
2008	431.14
2009	441.23
2010	449.21
2011	458.73
2012	468.25
2013	478.57
2014	489.12
2015	501.79
2016	514.64