Year	Number of
1990	445.76
1991	445.14
1992	442.58
1993	444.9
1994	438.13
1995	441.25
1996	429.56
1997	423.75
1998	417.2
1999	412.92
2000	410.17
2001	403.89
2002	398.55
2003	398.9
2004	398.12
2005	401.52
2006	405.43
2007	409.16
2008	414.74
2009	420.63
2010	429.22
2011	436.54
2012	443.38
2013	450.77
2014	458.41
2015	466.87
2016	478.02