Year	Number of
1990	258.88
1991	271.32
1992	284.47
1993	298.14
1994	312.87
1995	329.18
1996	328.34
1997	327.91
1998	327.81
1999	327.84
2000	327.97
2001	341.97
2002	356.93
2003	372.63
2004	389.47
2005	407.63
2006	431.42
2007	457
2008	484.44
2009	513.52
2010	544.77
2011	563.31
2012	582
2013	600.92
2014	621.4
2015	642.51
2016	665.17