Year	Number of
1990	272.83
1991	280.57
1992	283.54
1993	277.09
1994	276.36
1995	273.79
1996	275.22
1997	272.7
1998	276.64
1999	278.69
2000	277.35
2001	285.31
2002	286.64
2003	283.12
2004	278.83
2005	274.78
2006	273.56
2007	272.43
2008	277.33
2009	278.13
2010	278.95
2011	288.9
2012	297.71
2013	306.86
2014	319.04
2015	334.48
2016	347.46