Year	Number of
1990	206.8
1991	212.76
1992	218.51
1993	224.21
1994	230.53
1995	237.58
1996	244.94
1997	253.47
1998	262.33
1999	271.52
2000	279.15
2001	281.24
2002	286.06
2003	290.18
2004	294.83
2005	301.02
2006	304.74
2007	307.57
2008	310.99
2009	316.26
2010	321.51
2011	331.88
2012	344.26
2013	358.79
2014	374.99
2015	389.66
2016	404.91