Year	Number of
1990	41.01
1991	42.54
1992	44.21
1993	46.11
1994	48.02
1995	50.13
1996	51.91
1997	54.2
1998	56.49
1999	58.95
2000	61.45
2001	63.14
2002	64.92
2003	66.67
2004	68.48
2005	70.13
2006	71.62
2007	74.44
2008	76.71
2009	78.72
2010	80.59
2011	83.21
2012	85.59
2013	87.87
2014	90.48
2015	93.64
2016	96.93