Year	Number of
1990	520.72
1991	543.77
1992	558.4
1993	572.36
1994	563.36
1995	564.76
1996	543.88
1997	534.64
1998	512.41
1999	486.11
2000	469.02
2001	462.84
2002	450
2003	436.97
2004	437.15
2005	434.65
2006	430.43
2007	426.56
2008	430.39
2009	435.92
2010	443.7
2011	448.66
2012	438.58
2013	435.17
2014	435.27
2015	452.91
2016	469.83