Year	Number of
1990	301.31
1991	308.05
1992	315.38
1993	324.47
1994	334.59
1995	345.81
1996	355.9
1997	365.92
1998	376.56
1999	381.28
2000	389.47
2001	388.07
2002	390.6
2003	396.04
2004	404.39
2005	415.78
2006	431.96
2007	446.36
2008	461.75
2009	477.65
2010	495.34
2011	515.11
2012	537.27
2013	561.92
2014	592.71
2015	623.78
2016	659.23