Year	Number of
1990	453.57
1991	446.13
1992	451.2
1993	444.01
1994	448.09
1995	447.14
1996	440.03
1997	446.68
1998	443.11
1999	449.1
2000	448.13
2001	437.85
2002	429.85
2003	433.02
2004	436.62
2005	436.59
2006	438
2007	430.04
2008	441.39
2009	444.01
2010	439.17
2011	443.26
2012	443.65
2013	444.77
2014	445.68
2015	453.31
2016	461.03