Year	Number of
1990	142.49
1991	145.14
1992	148.11
1993	151.31
1994	154.67
1995	158.32
1996	161.37
1997	164.72
1998	168.29
1999	171.98
2000	175.91
2001	179.61
2002	183.51
2003	187.63
2004	191.89
2005	196.64
2006	202.39
2007	208.26
2008	215
2009	222.16
2010	230.08
2011	237.13
2012	245.16
2013	253.73
2014	262.8
2015	272.32
2016	283.04