Year	Number of
1990	171.2
1991	177.74
1992	184.22
1993	191.24
1994	199.25
1995	206.41
1996	212.23
1997	217.64
1998	221.2
1999	222.27
2000	224.17
2001	224.54
2002	226.57
2003	229.37
2004	233.21
2005	237.79
2006	242.7
2007	244.69
2008	249.84
2009	255.78
2010	262.77
2011	267.29
2012	269.4
2013	275.77
2014	280.93
2015	286.64
2016	293.81