Year	Number of
1990	260.24
1991	262.77
1992	262.92
1993	263.71
1994	262.65
1995	264.18
1996	265.75
1997	268.3
1998	272.33
1999	269.06
2000	269.09
2001	268.39
2002	267.17
2003	266.06
2004	265.43
2005	269.33
2006	273.38
2007	275.73
2008	278.39
2009	280.73
2010	283.61
2011	282.39
2012	282.8
2013	283.13
2014	284.21
2015	284.32
2016	285.62