Year	Number of
1990	237.88
1991	248.15
1992	260.07
1993	266.79
1994	278.51
1995	289.66
1996	293.68
1997	307.87
1998	311.42
1999	322.17
2000	331.27
2001	349.86
2002	366.66
2003	382.58
2004	398.78
2005	407.58
2006	415.56
2007	420.71
2008	437.04
2009	454.53
2010	472.99
2011	489.57
2012	509.64
2013	527.32
2014	543.03
2015	559.14
2016	576.01