Year	Number of
1990	182.66
1991	181.07
1992	178.44
1993	177.51
1994	179.27
1995	175.59
1996	191.43
1997	203.42
1998	216.42
1999	219.44
2000	222.6
2001	221.28
2002	221.56
2003	216.76
2004	216.87
2005	217.37
2006	223.15
2007	230.5
2008	239.49
2009	249.02
2010	257.45
2011	267.25
2012	275.53
2013	283.76
2014	290.53
2015	299.23
2016	309.54