Year	Number of
1990	84.47
1991	84.43
1992	83.93
1993	83.44
1994	83.49
1995	84.47
1996	86.45
1997	89.86
1998	94.54
1999	99.61
2000	104.78
2001	108.4
2002	112.11
2003	116.23
2004	120.73
2005	125.76
2006	130.88
2007	136.42
2008	142.89
2009	149.92
2010	157.55
2011	165.65
2012	174.47
2013	183.82
2014	193.39
2015	203.03
2016	212