Year	Number of
1990	155.43
1991	160.45
1992	169.85
1993	179.67
1994	189.54
1995	202.47
1996	205.23
1997	204.44
1998	209.13
1999	212.95
2000	219.01
2001	222.51
2002	223.34
2003	225.45
2004	231.16
2005	230.66
2006	234.35
2007	234.62
2008	238.66
2009	242.71
2010	248.2
2011	252.95
2012	257.25
2013	259.14
2014	260.87
2015	262.16
2016	264.89