Year	Number of
1990	263.41
1991	267
1992	267.53
1993	268.81
1994	268.01
1995	269.85
1996	272.03
1997	275.21
1998	280.05
1999	277.34
2000	277.9
2001	276.4
2002	274.61
2003	272.97
2004	271.85
2005	274.91
2006	279.02
2007	280.91
2008	282.88
2009	284.83
2010	286.6
2011	285.16
2012	285.67
2013	285.63
2014	285.93
2015	284.72
2016	284.4