Year	Number of
1990	147.44
1991	155.19
1992	163.39
1993	171.73
1994	180.29
1995	189.65
1996	198.14
1997	207.32
1998	216.97
1999	226.8
2000	237.31
2001	252.12
2002	268.08
2003	285.05
2004	303.64
2005	324.2
2006	344.71
2007	366.75
2008	390.71
2009	416.54
2010	444.95
2011	458.46
2012	472.46
2013	486.9
2014	501.64
2015	516.71
2016	532.52