Year	Number of
1990	479.67
1991	468.29
1992	456.48
1993	449.13
1994	429.31
1995	417.96
1996	405.4
1997	392.11
1998	382.49
1999	376.15
2000	355.8
2001	348.15
2002	332.35
2003	319.04
2004	302.06
2005	293.46
2006	281.91
2007	280.54
2008	274.08
2009	266.29
2010	265.03
2011	263.59
2012	256.15
2013	251.64
2014	248.06
2015	253.07
2016	258.89