Year	Number of
1990	311.64
1991	312.24
1992	309.16
1993	306.12
1994	308.22
1995	318.73
1996	323.71
1997	336.11
1998	353.57
1999	368.49
2000	378.35
2001	372.28
2002	363.52
2003	352.53
2004	343.13
2005	336.31
2006	349.97
2007	365.08
2008	381.44
2009	398.55
2010	416.47
2011	440.09
2012	466.04
2013	495.12
2014	526.73
2015	560.95
2016	597.07