Year	Number of
1990	321.17
1991	326.4
1992	327.13
1993	325.42
1994	319.38
1995	323.17
1996	321.67
1997	318.88
1998	311.71
1999	305.64
2000	298.51
2001	289.65
2002	283.6
2003	273
2004	269.6
2005	266.7
2006	267.7
2007	268.3
2008	269.45
2009	276.23
2010	268.65
2011	267.42
2012	262.32
2013	259.98
2014	264.74
2015	271.91
2016	278.81