Year	Number of
1990	80.84
1991	91.2
1992	103.22
1993	117.86
1994	133.41
1995	149.59
1996	157.1
1997	164.95
1998	170.65
1999	177.69
2000	185.11
2001	193.09
2002	201.01
2003	210.16
2004	219.96
2005	229.35
2006	236.59
2007	242.34
2008	248.17
2009	254.28
2010	261.49
2011	270.64
2012	283.27
2013	299.09
2014	316.31
2015	334.73
2016	354.12