Year	Number of
1990	222.24
1991	219.58
1992	220.42
1993	220.99
1994	223.85
1995	224.14
1996	223.27
1997	220.79
1998	211.52
1999	206.81
2000	201.63
2001	197.6
2002	192.61
2003	181.83
2004	179
2005	178.39
2006	180.11
2007	184.73
2008	188.08
2009	196.2
2010	205.57
2011	211.97
2012	212.44
2013	216.39
2014	226.7
2015	230.12
2016	235.11