Year	Number of
1990	205.44
1991	207.28
1992	216.02
1993	225.22
1994	235.38
1995	249.83
1996	269.32
1997	287.19
1998	292.46
1999	299.8
2000	313.39
2001	316.96
2002	330.01
2003	346.19
2004	358.36
2005	377.56
2006	389.63
2007	399.73
2008	411.08
2009	422.61
2010	434.79
2011	440.85
2012	449.41
2013	453.05
2014	464.34
2015	490.15
2016	510.76