Year	Number of
1990	321.4
1991	330.23
1992	336.43
1993	339.92
1994	338.75
1995	345.11
1996	345.56
1997	345.95
1998	344.29
1999	345.38
2000	343.96
2001	338.66
2002	338.41
2003	334.67
2004	342.1
2005	346.67
2006	348.43
2007	349.06
2008	352.17
2009	362.17
2010	358.26
2011	361.58
2012	360.9
2013	364.66
2014	377.24
2015	393.71
2016	410.16