Year	Number of
1990	112.87
1991	113.74
1992	108.78
1993	104.74
1994	102.55
1995	101.59
1996	98.25
1997	93.91
1998	91.29
1999	87.68
2000	83.43
2001	81.4
2002	79.35
2003	77.52
2004	76.98
2005	74.51
2006	73.69
2007	74.22
2008	72.91
2009	71.9
2010	72.5
2011	72.26
2012	72.04
2013	71.35
2014	71.13
2015	72.58
2016	73.72