Year	Number of
1990	451.49
1991	467.53
1992	483.98
1993	500.32
1994	518
1995	536.97
1996	509.52
1997	482.55
1998	456.88
1999	432.52
2000	409.68
2001	424.8
2002	441.14
2003	459.88
2004	479.68
2005	500.41
2006	518.76
2007	537.31
2008	556.23
2009	576.51
2010	598.95
2011	606.4
2012	614.91
2013	623.27
2014	632.26
2015	642.3
2016	654