Year	Number of
1990	307.57
1991	309.97
1992	312.72
1993	315.97
1994	319.34
1995	322.91
1996	319.46
1997	316.04
1998	313.31
1999	310.71
2000	308.38
2001	314.82
2002	321.58
2003	329.19
2004	337.07
2005	345.32
2006	356.47
2007	367.99
2008	380.68
2009	393.89
2010	407.76
2011	424.76
2012	442.67
2013	461.88
2014	482.06
2015	503.27
2016	525.51