Year	Number of
1990	154.07
1991	161.21
1992	165.73
1993	170.21
1994	173.96
1995	179.25
1996	187.2
1997	198.95
1998	209.32
1999	227.98
2000	235.44
2001	243.86
2002	251.69
2003	264.05
2004	274.83
2005	286.42
2006	286.4
2007	295.82
2008	296.72
2009	304.94
2010	310.73
2011	310.66
2012	313.59
2013	311
2014	304.76
2015	305.33
2016	296.87