Year	Number of
1990	230.29
1991	226.68
1992	227.83
1993	225.28
1994	223.2
1995	221.38
1996	216.8
1997	216.87
1998	217.42
1999	224.3
2000	231.35
2001	235.11
2002	243.93
2003	251.01
2004	261.77
2005	269.95
2006	278.07
2007	284.14
2008	289.98
2009	300.14
2010	308.66
2011	316.47
2012	324.68
2013	331.94
2014	339.31
2015	347.24
2016	356.35