Year	Number of
1990	152.36
1991	156.55
1992	160.32
1993	173.23
1994	180.63
1995	193.89
1996	198.64
1997	199.77
1998	205.3
1999	212.56
2000	218.94
2001	226.01
2002	224.73
2003	227.98
2004	226.04
2005	231.41
2006	237.72
2007	239.13
2008	241.08
2009	242.75
2010	249.21
2011	257.53
2012	266.93
2013	273.01
2014	277.72
2015	281.37
2016	286.95