Year	Number of
1990	113.73
1991	115.82
1992	120.02
1993	125.15
1994	133.69
1995	138.42
1996	138.01
1997	138.66
1998	143.42
1999	149.1
2000	152.93
2001	159.3
2002	165.24
2003	171.57
2004	179.08
2005	189.09
2006	193.88
2007	197.68
2008	207.21
2009	215.19
2010	226.8
2011	237.87
2012	245.46
2013	253.61
2014	261.52
2015	260.29
2016	262.9