Year	Number of
1990	94.8
1991	100.9
1992	107.41
1993	115.11
1994	123.23
1995	131.84
1996	140.87
1997	150.42
1998	161.66
1999	173.47
2000	185.91
2001	196.55
2002	207.62
2003	220.15
2004	233.24
2005	247.02
2006	260.29
2007	274.01
2008	288.91
2009	304.56
2010	321.18
2011	339
2012	358.17
2013	378.97
2014	401.18
2015	424.86
2016	450.93