Year	Number of
1990	72.64
1991	74.06
1992	76.6
1993	75.42
1994	75.86
1995	77.19
1996	80.54
1997	81.49
1998	84.99
1999	89.38
2000	91.51
2001	93.82
2002	94.5
2003	95.71
2004	96.61
2005	98.17
2006	100.54
2007	100.78
2008	102.09
2009	105.47
2010	111.23
2011	111.59
2012	113.22
2013	114.8
2014	116.58
2015	118.3
2016	120.26