Year	Number of
1990	183.61
1991	185.44
1992	189.66
1993	193.47
1994	198.52
1995	202.56
1996	208.16
1997	209.42
1998	211.97
1999	216.17
2000	221.01
2001	227.15
2002	229.5
2003	233.91
2004	239.79
2005	244.04
2006	248.14
2007	252.08
2008	257.74
2009	263.12
2010	268.65
2011	275.28
2012	281.1
2013	287.9
2014	294.61
2015	301.83
2016	309.04