Year	Number of
1990	359.62
1991	357.54
1992	356.12
1993	354.37
1994	353.05
1995	352.21
1996	339.43
1997	327.01
1998	315.06
1999	304.06
2000	294.18
2001	296.62
2002	299.83
2003	304.22
2004	308.96
2005	314.07
2006	321.28
2007	328.66
2008	337.38
2009	346.67
2010	356.72
2011	368.53
2012	381.12
2013	394.47
2014	408.31
2015	422.58
2016	437.7