Year	Number of
1990	377.85
1991	390.89
1992	389.27
1993	386.34
1994	375.01
1995	372.53
1996	361.95
1997	332.1
1998	325.48
1999	317.66
2000	315.89
2001	318.02
2002	324.85
2003	328.61
2004	333.42
2005	338.26
2006	347.45
2007	356.49
2008	364.13
2009	374.9
2010	382.55
2011	397.31
2012	401.22
2013	417.95
2014	431.7
2015	449.13
2016	465.06