Year	Number of
1990	219.71
1991	227.9
1992	237.23
1993	247.59
1994	258.83
1995	271.04
1996	283.57
1997	297.04
1998	311.32
1999	326.91
2000	344.07
2001	356.52
2002	370.15
2003	384.32
2004	399.26
2005	414.93
2006	417.65
2007	419.97
2008	422.9
2009	426.86
2010	432.34
2011	449.27
2012	468.72
2013	490.62
2014	514.17
2015	539.08
2016	564.75