Year	Number of
1990	271.36
1991	285.06
1992	293.38
1993	311.41
1994	329.48
1995	330.05
1996	323.66
1997	326.54
1998	336.97
1999	337.68
2000	345.44
2001	351.46
2002	380.82
2003	403.02
2004	438.11
2005	464.5
2006	495.97
2007	510.01
2008	517.51
2009	526.12
2010	528.52
2011	548.91
2012	561.98
2013	574.61
2014	594.9
2015	611.05
2016	629.18