Year	Number of
1990	259.93
1991	266.65
1992	273.67
1993	280.93
1994	289.86
1995	298.47
1996	307.28
1997	316.87
1998	326.04
1999	329.27
2000	335.75
2001	345.87
2002	351.6
2003	362.44
2004	372.23
2005	384.05
2006	394.67
2007	405.34
2008	414.3
2009	428.37
2010	438.99
2011	451.76
2012	468.46
2013	486.24
2014	502.01
2015	518.75
2016	537.41