Year	Number of
1990	154.2
1991	154.41
1992	155.04
1993	157.88
1994	157.91
1995	159.32
1996	161.46
1997	162.87
1998	165.07
1999	165.29
2000	166.78
2001	168.51
2002	172.33
2003	177.31
2004	180.84
2005	184.65
2006	187.76
2007	191.06
2008	196.26
2009	202.72
2010	209.96
2011	217.67
2012	226.09
2013	235.13
2014	245.05
2015	255.91
2016	267.22