Year	Number of
1990	276.46
1991	282.88
1992	290.77
1993	300.4
1994	306.06
1995	313.72
1996	322.33
1997	333.92
1998	345.32
1999	359.64
2000	378.74
2001	389.65
2002	400.45
2003	412.91
2004	426.35
2005	440.57
2006	449.46
2007	461.83
2008	469.36
2009	477.11
2010	487.4
2011	497.94
2012	508.41
2013	519.94
2014	532.35
2015	545.75
2016	559.58