Year	Number of
1990	305.7
1991	305.64
1992	304.25
1993	302.49
1994	301.56
1995	302.12
1996	308.19
1997	316.64
1998	327.72
1999	339.5
2000	351.57
2001	362.74
2002	374.39
2003	386.52
2004	399.24
2005	412.8
2006	425.17
2007	437.42
2008	449.9
2009	463.06
2010	477.24
2011	489.31
2012	502.36
2013	515.68
2014	530.19
2015	546.04
2016	566.96