Year	Number of
1990	263.48
1991	266.29
1992	269.21
1993	272.07
1994	274.96
1995	279.03
1996	282.25
1997	284.64
1998	288.73
1999	292.36
2000	301.93
2001	306.34
2002	317.2
2003	331.81
2004	350.82
2005	370.69
2006	388.12
2007	405.8
2008	424.34
2009	442.84
2010	468.46
2011	491.94
2012	515.5
2013	535.51
2014	558.7
2015	582.26
2016	608.88