Year	Number of
1990	244.09
1991	251.88
1992	262.45
1993	275.48
1994	284.87
1995	294.92
1996	300.56
1997	307.02
1998	316
1999	326.72
2000	338.48
2001	348.3
2002	358.09
2003	367.94
2004	378.22
2005	390.23
2006	400.23
2007	410.82
2008	421.99
2009	433.27
2010	443.96
2011	452.89
2012	462.13
2013	472.02
2014	482.62
2015	493.99
2016	503.83