Year	Number of
1990	59.77
1991	61.76
1992	63.81
1993	65.81
1994	67.87
1995	69.98
1996	72.22
1997	74.24
1998	76.23
1999	78.53
2000	80.99
2001	83.06
2002	85.18
2003	87.48
2004	89.88
2005	92.15
2006	94.19
2007	96.53
2008	98.79
2009	100.98
2010	103.05
2011	104.94
2012	107.04
2013	109.46
2014	112.04
2015	114.67
2016	117.31