Year	Number of
1990	318.68
1991	312.12
1992	305.34
1993	300
1994	295.89
1995	291.88
1996	290.11
1997	287.73
1998	285.2
1999	283.13
2000	281.06
2001	283.15
2002	285.32
2003	287.6
2004	290.25
2005	292.92
2006	290.05
2007	286.97
2008	284.06
2009	281.48
2010	279.03
2011	280.41
2012	281.97
2013	283.59
2014	285.28
2015	287.03
2016	288.97