Year	Number of
1990	446.65
1991	453.58
1992	460.99
1993	471.05
1994	490.46
1995	507.66
1996	521.61
1997	547.05
1998	548.62
1999	562.55
2000	555.39
2001	551.31
2002	545.51
2003	538.09
2004	537.76
2005	531.76
2006	532.97
2007	526.26
2008	509.82
2009	503.27
2010	495.79
2011	482.71
2012	470.9
2013	464.08
2014	453.24
2015	447.65
2016	442