Year	Number of
1990	61.78
1991	62.66
1992	63.51
1993	63.62
1994	62.97
1995	63.14
1996	63.5
1997	65.31
1998	68.14
1999	70.78
2000	74.38
2001	78.97
2002	84.14
2003	89.44
2004	92.86
2005	97.51
2006	101.4
2007	104.27
2008	106.92
2009	109.08
2010	110.8
2011	111.28
2012	112.67
2013	114.66
2014	116.76
2015	118.81
2016	120.78