Year	Number of
1990	80.85
1991	91.4
1992	103.1
1993	116.62
1994	130.73
1995	145.29
1996	152.09
1997	159.24
1998	164.65
1999	170.42
2000	176.75
2001	183.93
2002	191.45
2003	199.76
2004	208.93
2005	219.14
2006	224.38
2007	230.21
2008	236.93
2009	244.25
2010	252.27
2011	265.72
2012	280.31
2013	295.65
2014	312.34
2015	330.49
2016	350.58