Year	Number of
1990	245.82
1991	256.53
1992	267.68
1993	279.42
1994	292.29
1995	306.68
1996	315.58
1997	325.76
1998	337.04
1999	349.33
2000	362.67
2001	370.82
2002	378.72
2003	387.35
2004	396.43
2005	406.4
2006	415.02
2007	423.93
2008	434.46
2009	445.54
2010	457.48
2011	469.75
2012	483.53
2013	498.35
2014	514.12
2015	530.73
2016	548.46