Year	Number of
1990	99.39
1991	104.36
1992	110.13
1993	117.09
1994	125.74
1995	136.79
1996	153.91
1997	165.05
1998	180.68
1999	181.88
2000	192.55
2001	206.79
2002	219.39
2003	229.94
2004	233.31
2005	244.89
2006	249.17
2007	248.22
2008	246.95
2009	239.78
2010	236.24
2011	239.93
2012	248.73
2013	260.87
2014	275.02
2015	290.02
2016	304.83