Year	Number of
1990	236.23
1991	245.43
1992	254.64
1993	263.61
1994	273.17
1995	284.63
1996	290.97
1997	306.53
1998	300.23
1999	304.23
2000	319.53
2001	310.18
2002	329.29
2003	339.88
2004	347.43
2005	354.08
2006	360.33
2007	366.19
2008	387.27
2009	384.87
2010	393.89
2011	398.95
2012	405.52
2013	411.71
2014	420.1
2015	428.83
2016	439.2