Year	Number of
1990	127.06
1991	129.95
1992	133.31
1993	136.92
1994	140.82
1995	145.06
1996	147.86
1997	150.54
1998	153.82
1999	158.2
2000	162.93
2001	165.69
2002	169.07
2003	173.1
2004	177.69
2005	183
2006	189.96
2007	197.46
2008	205.64
2009	213.85
2010	222.9
2011	233.5
2012	244.95
2013	257
2014	269.79
2015	283.32
2016	296.68