Year	Number of
1990	113.9
1991	118.92
1992	124.36
1993	130.43
1994	136.93
1995	143.9
1996	149.37
1997	155.03
1998	160.91
1999	167.01
2000	173.35
2001	176.15
2002	179.21
2003	182.69
2004	187.33
2005	193.51
2006	206.31
2007	220.81
2008	237.22
2009	252.37
2010	265.01
2011	272.59
2012	276.52
2013	278.51
2014	281.75
2015	288.46
2016	296.11