Year	Number of
1990	254.45
1991	252.7
1992	251.99
1993	251.89
1994	254.76
1995	256.51
1996	255.97
1997	263.67
1998	270.66
1999	283.46
2000	301.31
2001	309.74
2002	321.15
2003	331.22
2004	343.4
2005	357.17
2006	361.33
2007	368.9
2008	373.31
2009	378.42
2010	388.18
2011	395.03
2012	402.34
2013	409.88
2014	416.24
2015	422.31
2016	428.82